Shared Flashcard Set

Details

Biology 3 Exam 2
ch 5,6, 10 and 27
149
Biology
Undergraduate 2
03/23/2012

Additional Biology Flashcards

 


 

Cards

Term
What is energy
Definition
The capacity to do work or cause change
Term
List two types of energy
Definition
1. Potential(stored energy) and kinetic energy (energy of movement)
Term
List examples of potential energy
Definition
Diver on a platform and water behind a dam are potential energy
Term
List examples of kinetic energy
Definition
Diver jumping off the platform and water moving through a dam are kinetic energy
Term
Explain active transport process
Definition
ATP attaches to protein and donates a phosphate (P), this causes the protein to open (relax) the channel to the outside and the substance is released or brought in. ATP becomes ADP after donating a phosphate.
Term
Exocytosis define
Definition
The process a cell uses to export bulky materials such as proteins and polysaccharides.

Movement of materials out of a cell by enclosing the material in a membranous sac that moves to the cell membrane then fuses with it to open on the outside of the cell allowing its contents to be expelled from the cell
Term
Exocytosis explain process
Definition
Transport vesicles full of the bulky substance fuse with the cell membrane. Once fully fused its contents are on the outside of the cell.

Moves waste out of the cell
Term
Endocytosis explain process
Definition
Opposite of exocytosis. A depression in the plasma membrane pinches in and forms a vesicle, surrounding the bulky substance and bringing it into the cell
Term
Endocytosis define
Definition
The process a cell uses to import bulky materials such as proteins and polysaccharides. Movement of large particles, including large molecules or entire microorganisms, into a cell by expanding extracellular material to surround the substance, creating a membrane-bound sac that enters the cytoplasm
Term
List 3 types of Endocytosis
Definition
1. Phagocytosis 2. Pinocytosis 3. Receptor-mediated endocytosis
NOTE: ALL USE ATPS
Term
Define Phagocytosis
Definition
“cellular eating” aka “invagination” for Particles cell engulfs a particle (bacteria, food) by wrapping extensions called pseudopodia around it and packaging it within a membrane-enclosed sac or vacuole. Not selective Once inside the cell, the vacule will fuse with Lysosomes for digestion
Term
Define Pinocytosis
Definition
“cellular drinking” for fluids the cell gulps droplets of fluid into tiny vesicles – not selective like receptor endocytosis is
Term
Define receptor-mediated endocytosis
Definition
Highly selective, receptor proteins for specific molecules are embedded in regions of the membrane-when activated by the correct specific molecule they will pinch around the solution and bring it into the cell inside a protein-coated vesicle
Term
Endo define
Definition
Taking in
Term
Exo define
Definition
Taking out (think kicking out an ex)
Term
Potential energy define
Definition
The energy that matter possesses as a result of its location or structure
Term
Define exergonic reaction
Definition

A chemical reaction that releases energy. Energy is given off into the environment. Need less energy to start than endergonic.

 

A molecule with high energy bound in it is broken to release the energy...creates smaller low energy molecules and frees the stored energy for cellular work

Term
Define endergonic reaction
Definition

A net input of energy yields products that are rich in potential energy. (the input of energy starts a reaction which creates a product rich in potential energy). Needs more energy to start than exergonic

 

the way that energy is harvested from the environment and stored by the cell for later use.

Term
Explain process of endergonic reaction
Definition

In photosynthesis energy from the sun is used to combine carbon dioxide and water (two low energy molecules) (aka the reactants) into glucose (a high energy molecule) (aka the product) with an oxygen byproduct. The plant stores glucose for later use in endergonic reactions

 

High energy is used to create packages of energy for storage and use elsewhere in the body.

Term
Is the hydrolysis of ATP exergonic or endogonic?
Definition
Exergonic – it releases energy
Term
Phosphorylation
Definition
The process of ATP transferring a phosphate group during hydrolysis to another molecule (an endergonic reaction)…most cellular work depends on ATP energizing molecules by phosphorylating them
Term
Define activation energy
Definition
The energy required to start a chemical reaction. (the amount of energy required for reactant molecules to move over the energy barrier so that the remainder of the chemical reaction can occur)
Term
define energy barrier
Definition
The high energy spurt required to start some chemical reactions
Term
Define catalyst
Definition

a substance that causes or accelerates a chemical reaction without itself being affected (not used up)

 

 

overcomes an energy barrier

Term
Enzymes
Definition
Molecules that function as biological catalysts that increase the rate of a reaction without being consumed by the reaction. Almost all are proteins…it speeds up a reaction by lowering the activation energy needed to start the reaction
Term
What effects the enzyme function
Definition
The environment. Enzymes rely on their 3-dimensional shape…temperature effects the shape, thereby affecting the ability of the enzyme to function. pH also effects enzymes
Term
Define cofactors as they pertain to enzymes
Definition
Nonprotein helpers for enzymes
Term
Define coenzyme
Definition
An organic cofactor (enzyme helper)
Term
If energy cannot be destroyed why do organisms have to absorb more energy to continue to function?
Definition
Because during the process of energy transformation some energy becomes unusable.
Term
How much of the energy in food do humans convert to usable energy?
Definition
40%
Term
What is the product of ATP conversion to energy?
Definition
ADP + P
Term
Define linked reactions
Definition
Aka coupled reactions: chemical reactions with a common intermediate in which energy is transferred from one side of the reaction to the other. An example is that of the reactant NAD+ H which becomes NADH through an exergonic reaction which is converted to NAD+ H through an endergonic reaction
Term
List 3 types of passive transport
Definition
1. Simple diffusion 2. Facilitated diffusion 3. Osmosis
Term
Define passive transport
Definition
Movement of substances across a membrane, going down a gradient of concentration, pressure or electrical charge. Does not require the cell to expend energy
Term
Define simple diffusion
Definition
the movement of molecules (usually water-soluble) across a membrane from high concentration to low concentration
Term
Osmosis
Definition
Diffusion of water across a selectively permeable membrane-that is, a membrane that is more permeable to water than to dissolved molecules
Term
Define energy-requiring transport
Definition
Movement of substances into or out of a cell using cellular energy
Term
List 3 energy-requiring transports
Definition
Active transport, Endocytosis, Exocytosis
Term
Define active transport
Definition

Movement of individual small molecules or ions through membrane-spanning proteins, using cellular energy, usually ATP.

 

often goes agains gradient from low to high which is why ATPs (energy) are required

Term
List the 3 functions of the cell membrane
Definition
1. Protection 2. Allow exchange of materials (import/export) 3. Allow cell communication
Term
What is the reason for cellular respiration
Definition
To make ATPs (harvest food energy)
Term
What are the main reactants and products of cellular respiration
Definition
The reactants are glucose and oxygen and the products are carbon dioxide, water and energy
Term
What kind of a reaction is cellular respiration
Definition
A chemical reaction
Term
Describe the process of cellular respiration
Definition
Oxygen (O2) is consumed as glucose is broken down to Carbon Dioxide (CO2) and water (H2O), the cell captures the energy released when the glucose bond is broken in ATP. Cellular respiration takes place in the mitochondria of all eukaryotic cells. Aka the aerobic harvesting of energy from food molecules by cells. Oxygen and Glucose are the reactants and Carbon Dioxide, water and ATPs are the product (plus small amount of heat)
Term
List the 3 main stages of cellular respiration
Definition
1. Glycolysis 2. Krebs Cycle aka the citric acid cycle 3. Electron Transport Chain “ETC”
Term
Describe Glycolysis process
Definition
Stage 1 of Cellular Respiration (anaerobic) : occurs in the cytoplasmic fluid of the cell outside the mitochondria. Creates 2 ATPs. Is the start of cellular respiration. A six-carbon glucose is split in half to form two molecules of pyruvic acid and 2 ATPs and (donate high energy electrons to NAD+ to create) 2 NADH, 2H+
Term
Describe Pyruvate oxidation and the citric acid (or Krebs) cycle
Definition

Stage 2 of Cellular Respiration (anaerobic): occurs in the matrix of the mitochondria. Creates 2 ATPs. The two molecules of pyruvic acid are oxidized by losing a carbon and change into a 2-carbon compound called Acetic Acid, this attaches to Coenzyme A and the new molecule moves on to the Citric Acid Cycle. Acetic Acid, ADP, P, 3 NAD+, and FAD are the reactants of the Citric Acid Cycle. The products of the Citric Acid Cycle are 2 CO2, 2 ATP, 3 NADH, 1 FADH2.

 

Note the NADH and FADH2 are necessary for the 3 stage...see ETC

Term
Which stage of cellular respiration makes the most ATPs?
Definition
Electron Transport (stage 3). It creates 34 while each of the other stages only creates 2 each. (38 total)
Term
Describe Electron Transport cycle
Definition
Stage 3 of cellular respiration (aerobic): occurs in the inner membrane of the mitochondria. only stage that requires oxygen. Creates the most ATPs. 1. NADH donates 2 electrons and 2 hydrogen to the protein at the beginning of the transport cycle. The electrons are picked up by a carrier protein and the 2 hydrogen are released outside the cell, raising the hydrogen gradient outside the cell, the electrons are moved to the next protein in the chain where FADH2 donates two more hydrogen. These hydrogen help to transfer (and are also released outside the cell again raising the exterior gradient), the two electrons to the last protein in the chain. In the last protein, the electrons bond with oxygen and hydrogen molecules to form water – the byproduct of the reaction is 4 hydrogen molecules which are also released outside the cell again raising the exterior hydrogen gradient. The NAD and FAD now return to Stage 2 of cellular respiration to pick up more hydrogen and start their part of the process over again. This process raises the hydrogen gradient outside the cell which creates the conditions needed to create ATPs in the last part of this process...the ATP Synthase complex.
Term
Define gradient and explain its importance
Definition
When a higher concentration of a molecule exists in one compartment compared to a neighboring compartment. Molecules will move from high concentrations to lower concentrations in an effort to reach equilibrium. This fact is used by cells to generate the energy needed to create ATPs. See ETC process
Term
Describe the process of ATP creation in the ATP Synthase complex
Definition

The last part of stage 3 of cellular respiration (after ETC). Responsible for the greatest number of ATPs. The donation of hydrogen by the electron transfer chain creates a molecular gradient with higher concentration outside the cell. As hydrogen enters the cell through the ATP Synthase complex enough energy is generated to bond ADP to 1 phosphate, creating ATP. This portion of the process creates 34 ATPs. Added to the 4 created in the other two stages, the entire process creates 38 ATPs.

 

relies on the laws of gradient of concentration across a semipermeable membrane (hydrogen gradient changed by ETC and hydrogen must move back across membrane to find equilibrium)

Term
List 2 types of fermentation
Definition
1. Lactate 2. Alcohol
Term
Define lactate as it pertains to fermentation
Definition
Is anaerobic harvest of food energy in humans and microorganisms (cheese, pickles)
Term
Define fermentation
Definition
The anaerobic harvest of food energy. Relies on glycolysis to produce ATP
Term
Define anaerobic
Definition
Little to no oxygen
Term
Describe where different types of proteins enter the cellular respiration cycle
Definition
1. Polysaccharides start at stage 1. 2. The glycerol in fats start at stage 1 and the fatty acids start at stage 2. 3. The amino acids in proteins start at stage 2 or 3.
Term
Define alcohol fermentation
Definition
Anaerobic harvest of food energy in yeasts. (beer, bread)
Term
List 3 types of asexual reproduction
Definition
1. Budding, 2. Fission, 3. Fragmentation/regeneration
Term
Define budding as it pertains to reproduction
Definition
A form of asexual reproduction. Splitting off new individuals from outgrowths of existing ones
Term
Define Fission as it pertains to reproduction
Definition
A form of asexual reproduction. The separation of a parent into 2 or more individuals of the same size. A sea anemone uses this form of reproduction
Term
Define fragmentation/regeneration
Definition
A form of asexual reproduction. The breaking of the parent body into several pieces, followed by regeneration, the regrowth of lost body parts
Term
Define hermaphroditism
Definition
Both male and female
Term
Describe the functions of the male reproductive system
Definition
to produce sperm/hormones & maintain secondary sexual characteristics. Controls: sex drive/behavior, body mass (bone/muscle/fat), body and facial hair, voice
Term
List the 3 glands in the male reproductive system
Definition
1. Seminal vesicle 2. Prostate gland 3. Bulbourethral gland
Term
Describe 7 parts of the male reproductive tract
Definition
1. Testis, 2. Vas deferens (ducts)/epididymis, 3. Urethra/duct, 4. Penis, 5. Seminal vesicles (glands), 6. Prostate gland, 7. Bulbourethral glands
Term
Define testes
Definition
A part of the male reproductive tract. Produces sperm and testosterone. Filled with seminiferous tubules that create sperm and interstitial cells that make testosterone.
Term
Define vas deferens (ducts) and epididymis
Definition
A part of the male reproductive tract. Store mature sperm (Epididymis), conducts sperm from testes to penis (vas deferens). Male has two of each one set on each side of penis
Term
Define urethra (duct)
Definition
A part of the male reproductive tract. Conducts semen from the two vas deferens and urine from the urinary bladder to the tip of the penis
Term
Define seminal vesicles (glands)
Definition
A part of the male reproductive tract. Secretes fluid into semen. Secretion is mainly fructos and provides food for the sperm.
Term
Define prostate gland
Definition
A part of the male reproductive tract. Secretes fluids into semen. Secretion is mucus.
Term
Define bulbourethral glands
Definition
A part of the male reproductive tract. Secretes fluid into semen. The fluid clears urine residue from the urethra and changes the pH from acid of urine to basic which is hospitable for sperm. Secretion is mucus and alkaline solution.
Term
Define seminal fluid
Definition
Comes from all three glands, includes sperm and enzymes and is about 2-5ml per ejaculation
Term
Define hormone regulation in males
Definition
Controls sex drive by making and secreting hormones includes the brain, the blood, pituitary and the reproductive tract (especially the testes)
Term
Describe hormone regulation in males
Definition
The hypothalamus makes and secretes GnRH (gonadotropin releasing hormones) hormones which enter the blood and are carried to the anterior pituitary which is stimulated to create LH (luteinizing hormones) (sperm regulating) and FSH (follicle stimulating hormones) (testosterone regulating). LH is carried to the interstitial cells and signals an increase in testosterone production while FSH is carried to the sertoli cells which stimulate sperm production. The testosterone from the interstitial cells is also carried to the sertoli cells and further stimulates sperm production. Sertoli cells also secrete another hormone, inhibin. When inhibin is carried back to the brain in signals the hypothalamus to cease GnRH production which slows down the process…until the level of inhibin drops sufficiently to start the process again.
Term
Spermatogenesis
Definition
Is the process of producing sperm with half the number of chromosomes as somatic cells (sperm cells)
Term
Define the process of spermatogenesis (4 steps)
Definition
Step 1: differentiation and onset of meiosis 1. One spermatogonium (diploid cell) splits into two daughter cells, Step 2: the prophase of meiosis 1: one of these  daughter cells continues on as a spermatogonium and the other becomes a primary spermatocyte. The spermatocyte splits into two spermatocytes (secondary spermatocytes or haploids) each having only 23 pairs of chromosomes and this completes meiosis 1. Step 3: Meiosis 2: each of the secondary spermatocytes splits into spermatids Step 4: Differentiation: the spermatids differentiate into sperm cells which, upon maturation (including growing flagellum, are released into the center of the seminiferous tubule and then migrate to the epididymis..
Term
Name the 5 parts of a sperm
Definition
1. Head, 2. Acrosome, 3. Mitochondria (middle piece) 4. Tail (flagellum), 5. Nucleus (in the head)
Term
Describe the importance of the acrosome of sperm
Definition
Contains a digestive enzyme that allows the sperm to enter the egg.
Term
Describe the functions of the female reproductive system
Definition
Functions: to produce eggs/hormones & maintain secondary sexual characteristics:
•Sex drive/ behavior
•Body mass (bone/muscle/ fat)
•Body hair
•Mammary glands
Term
List two female hormones
Definition
Estrogen and progesterone
Term
List 7 parts of the female reproductive tract
Definition
1. Ovary, 2. fimbria (opening of uterine tube), 3. Oviduct, 4. Uterine tube, 5. Uterus, 6. Cervix, 7. Vagina
Term
Define ovary
Definition

Part of the female reproductive tract. Produces eggs, estrogen, and progesterone.

 

the femail gonad

Term
Define fimbria
Definition
Part of the female reproductive tract. Has cilia that sweep egg into oviduct
Term
Define uterine tube
Definition
Aka oviduct. Part of the female reproductive tract. conducts egg to uterus; site of fertilization
Term
Define uterus
Definition
Part of the female reproductive tract. Muscular chamber where fetus develops
Term
Define cervix
Definition
Part of the female reproductive tract. Closes off lower end of uterus
Term
Define vagina
Definition
Part of the female reproductive tract. Receptacle for semen; birth canal
Term
List the 3 layers of the uterus
Definition
1 endometrium, 2. Perametrium, 3. Myometrium
Term
Define vulva
Definition
Folds of skin outside the vagina. Comprised of the labia majora (outside) and the labia minora (inside)
Term
Define endometrium
Definition
Lining of the uterus – provides nutrients for fertilized egg
Term
Define secondary sexual characteristics in males
Definition
body mass (bone/muscle/fat), body and facial hair, voice
Term
Define secondary sexual characteristics in females
Definition
Enlarged breasts, hips wider than men, body hair
Term
Define oogenesis
Definition
The creation of an ovum (in females)
Term
Describe the process of oogenesis
Definition
1. Oogonium in follicle is surrounded by follicular cells then changes into a Primary Oocyte. 2. Meiosis 1 splits the Primary Oocyte into a Secondary Oocyte with 23 chromosomes (which eventually becomes the ovum) and a separate tiny polar body (which degenerates and is absorbed by the body). The follicle continues to swell around the Secondary Oocyte as it matures until it bursts and releases the Secondary Oocyte into the Oviduct (this is called ovulation). The empty follicle then becomes the corpus luteum. If the Secondary Oocyte is not fertilized it will die in about 24 hours and will be absorbed by the body. The corpus luteum will also shrivel and die. If the Secondary Oocyte is fertilized by a sperm it will go through meiosis 2 in which it splits one more time one half becoming another polar body and one half becoming an ovum. As well, if fertilization occurs, the corpus leteum will survive for several months secreting hormones to maintain the pregnancy until the placenta is established.
Term
Describe the process of hormone regulation in females
Definition
The hypothalamus releases GnRH (gonadtropine releasing hormone) which enters the blood and is carried to the Pituitary gland which secrets FSH (follicle stimulating hormone) which is carried in the blood to the ovaries and stimulates egg cell development. The follicle of the egg secretes estrogen which travels in the blood to the hypothalamus and stimulates GnRH secretion (the positive feedback of the system). GnRH in the Pituitary gland also stimulates the release of LH (luteinizing hormone) which is carried in the blood to the ovaries and stimulates ovulation. The corpus luteum that results from ovulation secretes progesterone which is carried in the blood to the Hypothalamus and decreases the secretion of GnRH. (the negative feedback of the system).
Term
What do low levels of estrogen trigger?
Definition
Menstruation
Term
What do high levels of estrogen and progesterone trigger
Definition
Thickening of the endometrium
Term
FSH triggers?
Definition
FSH (Follicle Stimulating Hormone) Follicle growth
Term
LH triggers?
Definition
Luteinizing Hormone (LH) (Corpus Luteum) Ovulation
Term
Hypothalamus GnRH secretion is inhibited by?
Definition
A combination of estrogen and progesterone
Term
Hypothalamus GnRH secretion is stimulated by?
Definition
High levels of estrogen without high levels of progesterone
Term
What female ovulation body secretes progesterone
Definition
The corpus luteum
Term
What is the result of fertilization?
Definition
A zygote and embryonic development is triggered
Term
List the 7 steps of fertilization
Definition
1. A sperm touches the egg’s jelly coat, and its acrosome releases enzyme molecules, 2. The sperm’s acrosomal enzymes digest the egg’s jelly coat, 3. Proteins on the sperm head bind to egg receptors, 4. The plasma membranes of sperm and egg fuse, 5. The sperm nucleus enters the egg cytoplasm, 6. The vitelline layer of the egg separates and becomes impenetrable, 7. The nuclei of sperm and egg fuse
Term
Describe the process of fetal development
Definition
Fertilization occurs in the fallopian tube. The resulting zygote moves down the tube towards the uterus and starts cleavage which includes cells splitting until a solid ball of cells is formed. Implantation in the uterine wall occurs on day 7. The ball then becomes hollow turning into a blastocyst. The yolk sac forms around day 9. Then at 16 days it becomes a gastrula which divides the cells into 3 layers: mesoderm (red), ectoderm (blue) and endoderm (yellow). At 31 days the placenta is formed. At 8 weeks the embryo becomes a fetus.
Term
Gamete
Definition
Human egg or sperm
Term
Gonad
Definition
Testes or ovaries
Term
What hormone induces labor?
Definition
Oxytocin
Term
List the 3 stages of labor
Definition
1. Dilation of cervix (10cm) 2.explusion/delivery of fetus 3. Delivery of the placenta
Term
List the 5 primary methods of birth control
Definition
1. Abstinence 2. Hormonal 3. Sterilization 4. Barrier 5. Other
Term
Describe the way in which abstinence works as a form of birth control, risks and efficacy
Definition
Egg and sperm never make contact. No risks. 100% effective
Term
List the 4 most common forms of hormonal birth control
Definition
1. Combination birth control pill. 2. Mini pill 3. Depo Provera (injectable) 4. Implantables
Term
Describe the way in which the combination birth control pill works as a form of birth control, risks and efficacy
Definition
Synthetic estrogen and progesterone prevent ovulation. Increased risk of heart disease and blood clot especially in women over 35 who smoke. Does not protect against STDs. 99% effective
Term
Describe the way in which the mini pill works as a form of birth control, risks and efficacy
Definition
Progesterone only thickens mucus, impeding sperm ascent and the uterine lining is not prepared to support pregnancy. Increased risk of ovarian cyst. Does not protect against STD. 95% effective
Term
Describe the way in which Depo Provera (injectables) work as a form of birth control, risks and efficacy
Definition
Progesterone injections every 3 months- thickens mucus, impeding sperm ascent and the uterine lining is not prepared to support pregnancy. Irregular vaginal bleeding. Does not protect against STDs. 99% effective.
Term
Describe the way in which Implantables work as a form of birth control, risks and efficacy
Definition
Progesterone implant under the skin. Same as depo and mini pill. Off market. Does not protect against STDs. Effectiveness unknown
Term
List 2 most common forms of sterilization as it pertains to birth control
Definition
Female sterilization and Vasectomy (male sterilization)
Term
Describe the way in which female sterilization works as a form of birth control, risks and efficacy
Definition
Permanently blocks oviducts so no egg can enter uterus. Does not protect against STDs. 99.8% effective
Term
Describe the way in which vasectomy works as a form of birth control, risks and efficacy
Definition
Cutting both vas deferens prevents sperm from being from being ejaculated into the semen. Does not protect against STDs. 99.9% effective.
Term
List the 4 most common forms of barrier method birth control
Definition
Cervical cap. 2. Diaphragm 3. Female condom 4. Male condom
Term
Describe the way in which the cervical cap works as a form of birth control, risks and efficacy
Definition
Inserted against cervix before intercourse. Prevents sperm and egg contact. No known risks does not protect against STDs
Term
Describe the way in which the diaphragm works as a form of birth control, risks and efficacy
Definition
Inserted in vagina before intercourse. Prevents sperm and egg contact. No known risks does not protect against STDs
Term
Describe the way in which the female condom works as a form of birth control, risks and efficacy
Definition
Held against cervix by flexible ring. Prevents sperm and egg contact. No known risks
Term
Describe the way in which the male condom works as a form of birth control, risks and efficacy
Definition
Placed over penis before intercourse. Prevents sperm and egg contact. No known risks
Term
List the 3 most common forms of other birth control methods
Definition
Spermicides 2. Fertility awareness 3. Intrauterine device IUD
Term
Describe the way in which spermicides work as a form of birth control, and risks
Definition
When inserted into vagina 1 hour before intercourse kills sperm. No known risks does not protect against STDs
Term
Describe the way in which fertility awareness works as a form of birth control and risks
Definition
Abstinences 4 days before and 4 days after predicted time of ovulation. No known risks does not protect against STDs
Term
Describe the way in which intrauterine devices work as a form of birth control, and risks
Definition
Small plastic device inserted into uterus. Prevents fertilization and prevents the uterus from supporting a pregnancy. May increase risk of pelvic inflammatory disease
Term
List the 3 enzymes of DNA replication
Definition
DNA polymerase 2. DNA helicase 3. DNA ligase
Term
What does the enzyme DNA polymerase do?
Definition
bonds free nucleotides to DNA template strand to create the daughter strand during replication. Repairs DNA
Term
What does enzyme DNA helicase do?
Definition
Separates DNA strands
Term
What does enzyme DNA ligase do?
Definition
Glues DNA fragments together
Term
Describe the DNA replication process
Definition
The bonds of the nitrogenous bases of a parent or template strand of DNA are broken with the enzyme helicase. This occurs in multiple spots along the length of the DNA in bubbles or ‘origin of replication’. Replication always begins on the 3’ (prime) end of the DNA strand, therefore the side of the unzipped parent strand that has a 3 prime end is considered the leading strand and the other with a 5 prime end is considered the lagging end. The enzyme polymerase bonds free nucleotides to the leading strand in a continuous motion going towards its 5 prime end (creating the daughter strand). The polymerase also starts creating gapped sections of bonded free nucleotides on the other side moving away from the 3 prime end of the other unzipped strand. The enzyme ligase connects the gapped spaces to each other to make a single strand.
Term
List 3 types of RNA
Definition
mRNA (messenger-single strand), tRNA (transfer-contain amino acid), rRNA (ribosome-form ribosomes)
Term
Describe mRNA
Definition
Messenger, single strand RNA, encodes amino acid sequences by conveying genetic material from DNA to the translation machinery of the cell
Term
List 2 stages of DNA protein synthesis
Definition
Transcription and translation
Term
What can cause mutations in DNA
Definition
Replication errors, ultraviolet light and radiation. They can break the backbone or alter the bases so that they pair with the wrong free nucleotide
Term
Describe transcription as it pertains to protein synthesis
Definition
The transfer of genetic information from DNA into RNA . Occurs in nucleus. RNA polymerase (enzyme) connects with the promoter sequence of the DNA and starts RNA synthesis (called initiation). During the second phase of transcription, elongation, the RNA grows longer and peels away from the DNA template. In the 3rd phase, termination, the enzyme RNA polymerase reaches the sequence the signals the end of the gene (terminator) and detaches from the DNA. The mRNA then moves towards the nuclear pores to exit the nucleus and on the way is modified to remove introns, splice exons together and add a cap and tail to protect it from the environment of the cell. It then exits the nucleus via a nuclear pore and travels to the ribosomes to begin translation.
Term
Define introns
Definition
Internal noncoding regions of genes (intervening sequences). These are removed from RNA before it exits the nucleus and begins transcription of proteins
Term
Define exons
Definition
Coded regions of genes. The part that is expressed.
Term
What is the language of nucleic acid
Definition
Codons (groups of three nucleotides) ex: start codon AUG
Term
Define RNA splicing
Definition
The process by which the introns of RNA are removed and the exons are spliced together and a cap and tail are added to the RNA before it exits the nucleus.
Term
Describe translation as it pertains to protein synthesis
Definition
The transfer of information from mRNA (messenger) into a protein using tRNA (transfer). tRNA pick up the correct amino acid and recognizes the appropriate codons in the mRNA. tRNA has a triplet of bases called anticodons which are complementary to condon triplets on mRNA. It also has an amino acid attachment site. ATP drives this process. Ribosomes catalyze the synthesis of polypeptides and place tRNA and mRNA close together. 1. Codon recognition 2. Peptide bond formation 3. translocation
Term
Describe ribosomes as they pertain to protein synthesis
Definition
They are composed of ribosomal RNA (rRNA) and consist of two subunits.
Term
What is the significance of AUG
Definition
Start codon for protein synthesis carried by mRNA and used by tRNA to place MET as the first amino acid in the protein chain.
Term
List the 5 steps in the flow of genetic information from DNA to RNA to protein
Definition
1. Transcription 2. Translation/amino acid attachment 3. Initiation of polypeptide synthesis 4. Elongation 5. Termination
Term
Describe codon recognition as it pertains to translation
Definition
Anticodon of an incoming tRNA molecule, carrying its amino acid, pairs with the mRNA codon in the A site of the ribosome.
Term
Describe initiation of polypeptide synthesis as it pertains to translation
Definition
The polypeptide separates from the tRNA in the P site and attaches, by a new peptide bond, to the amino acid carried by the rRNA in the A site. The ribosome catalyzes formation of the peptide bond.
Term
Describe translocation as it pertains to translation
Definition
The P site tRNA leaves the ribosome and the ribosome moves the remaining tRNA in the A site, to start the process over again. This continues until the ribosome encounters a stop codon.
Supporting users have an ad free experience!