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Cell Exam 1
ch 1-3
88
Biology
Undergraduate 3
09/08/2011

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Term
genetic information flow
Definition
DNA transcribed into RNA then translated into proteins
Term
microscopes invented when?
Definition
17th century
Term
microscopes important to biology
Definition
light, transmission electron, scanning electron
Term
robert hooke
Definition
1665

set of lenses

visualizd cork cell walls
Term
matthias schleiden amd Theodor Schwann
Definition
1838/1839

all living organisms are made of cells
Term
rudolf virchow
Definition
mid 1800s

all cells arise from other cells
Term
louis pasteur
Definition
1860s

confirmed cell theory by observing a plant cell for 2.5 hours
Term
tissue in plants and animals
Definition
cells tightly packed

loose extracellular matrix (ECM)
-proteins/fibers in polysaccharide gel
Term
cell size
Definition
usually 5-20 micrometers

10 times smaller than eyes can resolve
Term
light microscope
Definition
magnifies 1000 times smaller than eyes can see

can usually view outer cell boundary, nucleus, and some cytoplasm detail but no small cell component visualization

bright light source

set of lenses arranged to focus images

specimen must be thin enough for light to pass through
Term
electron microscope
Definition
1000 times smaller than light microscope

2 types: scanning electron microscope and transmission electron microscope
Term
steps for preparing tissue for microscopy
Definition
1. fixation - preserve tissue sample in native state

2. embedding-replace cell's water with wax or plastic resin to provide support

3. section- produce thin slice of sample

4. stain-impart contrast
Term
scanning electron microscope
Definition
visual surface structures

uses electrons, not light...and magnets, not lenses

image generated by electrons bouncing off specimen-reveals 3D image
Term
transmission electron microscope
Definition
similar to SEM but no 3D image

electrons pass through specimen or bounce off densely stained structures (stain provided by processing with heavy metals)

dense area=dark

less dense area=gray and white
Term
prokaryotic cells
Definition
DNA lies in cytoplasm

has ribosomes
Term
bacteria shapes
Definition
spherical, rod, corkscrew
Term
bacteria has...
Definition
cell wall around plasma membrane

cytoplasm and DNA, but no organized internal structures

varied oxygen requirements

use for many sources of food
-inorganic compounds
-some may photosynthesize
Term
2 domains of prokaryotic organisms
Definition
eubacteria and archaea
Term
Eubacteria
Definition
regular bacteria
Term
Archaea
Definition
found in hostile environments
-high salt
-high temp
-acid
-sewage treatment plants
-ice
Term
eukaryotic cell
Definition
some can be single cell (yeast, amoeba)

most multicellular
Term
chromatin
Definition
DNA associated with proteins
Term
chromosomes
Definition
grouping of condensed chromatin

visible/threadlike
Term
nuclear envelope
Definition
double membrane that encloses the nucleus
Term
nuclear pores
Definition
communicate between nucleoplasm and cytoplasm

small openings in envelope
Term
mitochondria
Definition
4 components: outer membrane, inner membrane (highly folded-cristae), intermembrane space, matrix

contains own DNA and can divide into 2 new mitochondria

evolved from engulfed bacteria?

powerhouse of cell (generates ATP)

functions in cellular respiration
Term
chloroplasts
Definition
similar to but more complex than mitochondria
-double membrane
-have their own DNA and can divide
-evolved from symbiosis?
Term
internal membranes
Definition
import raw materials

export manufactures substances, waste products

move molecules within cell
Term
endoplasmic reticulum
Definition
irregular maze of interconnected spaces
-single membrane continuous with nuclear membrane

production of molecules for cell and for export
Term
2 types of ER
Definition
Rough ER- contains ribosomes on surface (synthesizes proteins)

Smooth ER- no ribosomes (synthesizes and metabolizes lipids)
Term
Golgi apparatus
Definition
stacks of flattened membrane-bound sacs

modifies proteins and lipids produced in the ER
-adds sugars ->glycoproteins, glycolipids

directs proteins to various locations, usually outside of the cell

places molecules into vesicles
Term
vesicles
Definition
transport structures
-move materials around cell between other organelles
-move materials toward outer membrane for export

different types (ex:lysosomes and peroxisomes)
Term
endocytosis
Definition
import into cell

molecules/other cells usually fuse with lysosome (digestion)
Term
exocytosis
Definition
export
Term
lysosomes
Definition
vesicles known as digestive organs of the cell

contains enzymes for breakdown

digests food, recycles materials, releases nutrients, eliminates wastes
Term
peroxisomes
Definition
removes hydrogen peroxide generated from lipid metabolism
Term
cytosol
Definition
concentrated aqueous gel
-part of cytoplasm not partitioned within intracellular membranes

can be largest cell component

site of many chemical reactions

ribosomes producing proteins for cell metabolism found here
Term
ribosomes
Definition
non-membrane-bound structures responsible for protein synthesis

complex of protein and RNA

made of 1 small subunit and 1 large subunit

holds molecules needed for protein synthesis in proper places

formation of peptide bonds that hold amino acids together in a protein

NOT AN ORGANELLE!
Term
cytoskeleton
Definition
elaborate network of filaments

give strength, shape, directed movement to cells

used by both animal and plant cells to move organelles around during cell division

constantly assembling and disassembling

3 filament types: actin, intermedate, microtubules
Term
actin fibers
Definition
thinnest fibers

generates contractile force
Term
intermediate
Definition
intermediate thickness

strengthens cell
Term
microtubules
Definition
thickest fibers

hollow tubes

rearranges to help separate chromosomes during cell division
Term
model organisms
Definition
organisms with fundamental properties conserved in all types of cells

easier to study in lab
Term
examples of model organisms
Definition
E. coli

Saccharomyces cerevisiae

arabidopsis

drosophila melanogaster

C. elegans
Term
E. coli
Definition
major prokaryotic model

rod-shaped bacteria

used as a factory in lab
Term
saccharomyces cerevisiae
Definition
eukaryotic model

brewer's yeast (used for bread and beer)

rigid cell wall & mitochondria
-"between plants and animals"

used to study cell division cycle
Term
arabidopsis
Definition
small weed

model plant

thousands of offspring in 8-10 weeks

used to understand genetics of flowering plants
Term
drosophila melanogaster
Definition
common fruit fly

used to study development and disease
-high gene similarity to humans
Term
C. elegans
Definition
nematode worm

precise time line of each developmental stage

first organism in which complete genome was sequenced
Term
"other" model examples
Definition
zebrafish (transparent embryos)

mouse (can manipulate genome to investigate role of individual gens in development and disease; transgenic mouse)

human (medical disease research)
Term
tritium
Definition
hydrogen isotope (^3H)

radioactive
Term
how much of organisms' weight composed of C, H, N, and O?
Definition
96.5%
Term
important biological elements
Definition
CHONSP
Term
exceptions to protons and neutrons remaining compacted and stagnant in nucleus
Definition
protons and neutrons move/change during radioactive decay, inside the sun, and in a nuclear reactor
Term
inert atoms
Definition
atoms with full electron shells prior to forming a chemical bond

non-reactive

ex: helium, neon, argon
Term
salt
Definition
substance held together solely by ionic bonds

will dissociate in water
Term
water makes up how much of cell's weight?
Definition
70%
Term
[H3O+] in pure water
Definition
10^-7
Term
sugars
Definition
CHO ratio is 1:2:1

>/= 3 monosaccharides is oligosaccharide

polysaccharides- many sugar molecules linked through their OH groups

cellular monosaccharides have backbones of 3-7 carbons

several monosaccharides have same CHO formula
Term
isomer
Definition
same formula but different structure (glucose, fructose)
Term
optical isomers
Definition
mirror images
Term
condensation reaction
Definition
synthesis reaction

OH of 1st monomer binds H of 2nd monomer

one water molecule removed and covalent bond formed between monomers

not random (particular enzymes catalyze condensation reactions)
Term
hydrolysis
Definition
breakdown reaction

requires water to break covalent bond

OH adds to one monomer, H to the other
Term
glucose
Definition
cell's central energy source

breaks down carbon dioxide (glycolysis, Krebs)

cell harnesses its energy during breakdown to produce ATP

cells store glucose as polysaccharides for future energy production (glycogen in animals, starch in plants)

used for mechanical support (cellulose, chitin)

linked to proteins (glycoproteins) and lipids (glycolipids)
Term
fatty acids
Definition
amphipathic (Polar COOH and nonpolar C-H)

stored in the form of triacylglycerols (3 fatty acids attached to glycerol (3C) backbone)
Term
saturated fat
Definition
no C to C double bond

maximum of H atoms
Term
unsaturated fats
Definition
one or more C to C double bond; oil
Term
amino acids
Definition
differ by side chain (R group)

all have carboxylic acids and amino groups linked to a central C atom

bonds between amino acids are peptide bonds
Term
proteins
Definition
C/N backbone formed from carboxyl, central C, and amino groups of individuals amino acids
Term
amino terminus
Definition
one end of protein (-NH2)
Term
carboxyl terminus
Definition
other end of the protein (-COOH)

additional amino acides are always added to this end during protein synthesis
Term
amino acids R groups
Definition
some form ions in solution
-basic: Lys, Arg, His
-acidic: Asp, Glu

Some uncharged, polar, and hydrophilic
-asn, gln, ser, thr, and tyr

some nonpolar and hydrophobic
-ala, val, leu, ile, pro, phe, met, trp, gly, cys
Term
nucleotides
Definition
make up DNA and RNA

made of N-containing base (purine/pyrimidine), 5 C sugar (ribose or deoxyribose), and 1-3 phosphate groups

store genetic info when polymerized into nucleic acids

chemical energy carriers (ATP)

components of coenzymes (CoA); important in metabolism

signaling molecules (cAMP); important in cell communication

nucleotides linked by phophodiester bonds
Term
improper conformation of macromolecules
Definition
improper/no function
Term
1st law of thermodynamics
Definition
energy can not be created or destroyed
Term
2nd law of thermodynamics
Definition
systems change spontaneously toward greater entropy
Term
photosynthesis
Definition
2 steps:
-energy stored in carriers (ATP and NADPH) and O2 is released
-ATP and NADPH drive carbon fixation to water and CO2 from air, and make sugars
Term
re-dox reactions
Definition
oxidation=loss of electrons/H+

reduction=gain of electrons/H+
Term
Enzymes
Definition
Selective (usually 1 enzyme for 1 reaction)

Unique shape, only particular substrate can fit

Remain unchanged so can be reused
Term
Substrate movement
Definition
Move through cytoplasm by diffusion
Term
Enzyme movement
Definition
relatively motionless
Term
Enzyme-substrate complex
Definition
Held by multiple weak interactions (h-bonds, ionic bonds, van der waals)

If wrong substrate gets into active site, no interactions will hold it and the substrate will leave quickly
Term
Michaelis constant
Definition
Concentration of substrate which occurs at 1/2 max value

Lower the value, the tighter the E-S interaction
Term
Carrier molecules
Definition
Energy released by catabolism is stored in their high energy covalent bonds Cleavage high energy bonds-> energy released Very negative free energy change  ATP, NADPH, NADH
Term
ATP
Definition
Most common carrier molecule

Bound by high energy phosphoanhydride bonds
Term
Kinase
Definition
Enzyme that catalyzes phosphate group transfer
Term
NADPH
Definition
Operates in anabolic reactions
Term
NADH
Definition
Works with catabolic reactions
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