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Lab Practical 1
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153
Biology
Undergraduate 1
03/07/2010

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Term
science
Definition
the orderly process of posing and answering questions about the natural world through repeated and unbiased experiments and observations, is a process
Term
scientific method
Definition
organized sequence of steps, include:
1) make insightful observations
2) pose & clarify testable questions
3) formulate hypothesis
4) do experiments to gather data
5) quantify the data
6) test the hypotheses
7) answer the questions and make conclusions
8) communicate findings
Term
hypothesis
Definition
a statement that clearly states the relationship between biological variables
Term
null hypothesis
Definition
a hypothesis that states that there is no difference, usually the most common way to state a clear/testable hypothesis
Term
alternative hypothesis
Definition
a hypothesis that states the difference between two things
Term
treatments
Definition
something that researchers administer to the experimental units
i.e. glucose or protein given to yeast
Term
replications
Definition
repeated measures of each treatment under the same conditions
Term
controls
Definition
standards for comparison, lacks the treatment variable
Term
mean
Definition
(know symbol) single number that represents the central tendency of the response variable, average
Term
range
Definition
a measure of variation between each set of replicates, equals the range between the highest and lowest values
Term
standard deviation
Definition
(SD), measure of variation, how far values are from the mean
Term
significantly different
Definition
differences between means must be due to the treatment and not just due to natural variation
Term
light microscope
Definition
a coordinated system of lenses arranged to produce an enlarged, focusable image of a specimen, can improve resolution as much as 1000-fold
Term
resolution
Definition
the ability to distinguish two points as separate points
Term
contrast
Definition
the amount of difference between the lightest and darkest parts of an image
Term
condenser lens
Definition
located immediately below the specimen, focuses light from the light source onto the specimen
Term
condenser iris diaphragm
Definition
a knurled ring or lever than can be opened and closed to regulate the amount of light reaching the specimen
Term
objectives
Definition
three or four lenses mounted on a revolving nosepiece, 4X 10X 40X and 400X
Term
ocular
Definition
the lens you look through, usually magnifies the object 10 times
Term
monocular microscopes
Definition
microscopes with only one ocular
Term
binocular microscopes
Definition
microscopes with two oculars
Term
body tube
Definition
metal casing through which light passes to the oculars
Term
stage
Definition
secures the glass slide on which the specimen is mounted
Term
ocular micrometer
Definition
small glass disk with thin lines numbered and etched in a row
Term
stage micrometer
Definition
glass slide having precisely spaces lines etched at known intervals
Term
depth of field
Definition
thickness of the object in sharp focus, varies w/difference objectives and magnifications
Term
working distance
Definition
distance between the objective lens and the specimen
Term
dissecting (stereoscopic) microscope
Definition
provides much larger working distance than compound microscope so specimens can be manipulated while observing, light source comes from above the specimen rather than below, always binocular, lower resolution & magnification
Term
cytology
Definition
study of cellular structure and function
Term
prokaryotes
Definition
bacteria & cyanobacteria, do not contain a membrane-bound nucleus or organelles
Term
prokaryotic cell structure
Definition
organelles (ribosomes, mesosomes-internal extensions of plasma membrane, & chromatin bodies-concentrations of DNA) suspended in cytoplasm, cytoplasm enclosed in plasma membrane, plasma membrane surrounded by cell wall, cell wall covered by a capsule, capsule has flagella (for movement) and pili (to attach bacteria to things or exchange genetic material)
Term
cyanobacteria
Definition
largest prokaryotes, also called blue-green algae, contain photosynthetic pigments in thylakoids,
surrounded by mucilaginous sheath, primary contributers to early oxygenation of ancient earth
Ex. Oscillatoria, Gloeocapsa,
Term
Bacteria
Definition
prokaryotic, smaller than cyanobacteria, no chlorophyll,
Ex. Lactobacillus
Term
Eukaryotic cells
Definition
contain membrane-bound nuclei and organelles, organelles are in cytoplasm, cytoplasm surrounded by plasma membrane,
Term
protoplast
Definition
all the material and organelles contained by the plasma membrane
Term
cytoplasmic streaming (cyclosis)
Definition
movement of the chloroplasts by the activity of the cytoplasm
Term
cell wall structure
Definition
primary cell wall (deposited during growth of the cell), middle lamella (substance holding walls of two adjacent cells together), plasmodesmata (cytoplasmic strands that penetrate cell walls and connect the protoplasm of adjacent cells)
Term
mitochondria
Definition
organelles, double membraned, inner membrane folds to form cristae, some DNA occurs here
Term
plastids
Definition
organelles where food is made and stored
Term
amyloplasts
Definition
plastids that store starch, are able to be stained with iodine
Term
Protists
Definition
large group of eukaryotic organisms that includes algae and sporozoans, single celled
Ex. Paramecium, Amoeba
Term
Amoeba
Definition
irregularly shaped protist, moves via amoeboid movement
Term
Amoeba structure
Definition
pseudopodia-temporary protrusions of the cell that allow for movement of the amoeba and also engulf food particles and digest them
contractile vacuole-accumulates and expels water and waste products
Term
Paramecium
Definition
single-celled protist, (know structure pg. 43)
Term
Brownian movement
Definition
random motion of molecules in biological systems caused by heat,
Term
diffusion
Definition
passive, directional movement of molecules across a gradient, affected by temperature, concentration, and pressure
Term
differentially permeable
Definition
a membrane that prevents the movements of some molecules but not others
Term
polar molecules
Definition
have positively charged areas and negatively charged areas
Term
nonpolar molecules
Definition
have no local areas of positive or negative charge
Term
dialysis
Definition
the separation of dissolved substances by means of their unequal diffusion through a differentially permeable membrane
Term
phenolphthalein
Definition
a pH indicatory that turns red in basic solutions
Term
iodine
Definition
a starch indicator that changes from yellow to dark blue in the presence of starch
Term
osmosis
Definition
diffusion of water across a differentially permeable membrane
Term
solution
Definition
a homogenous, liquid mixture of two or more kinds of molecules
Term
solvent
Definition
a fluid that dissolves substances
Term
solute
Definition
a substance dissolved in a solution
Term
hypotonic
Definition
a solution with a lower concentration of solutes
Term
hypertonic
Definition
a solution with a high concentration of solutes
Term
isotonic
Definition
two solutions that have equal concentrations of solute
Term
dependent variable
Definition
the variable being measured, always plotted on the y (or vertical) axis
Term
independent variable
Definition
the variable that you control/change, always plotted on the x (or horizontal) axis
Term
water potential
Definition
the combined effects of concentration and pressure such as that from cell walls, water will flow from area of high water potential to area of low water potential
Term
lysis
Definition
the destruction of a cell by the influx of water (causing the cell to burst)
Term
hemolysis
Definition
the destruction of a red blood cell by lysis
Term
plasmolysis
Definition
shrinking of the cytoplasm of a plant cell in response to diffusion of water out of the cell and into a hypertonic solution, cellular membrane pulls away from the cell wall
Term
hydrophilic
Definition
"water loving", the phosphate group and glycerol of a phospholipid
Term
hydrophobic
Definition
"water fearing", the fatty acids of phospholipids
Term
amphipathic
Definition
molecules with both hydrophilic and hydrophobic regions
Ex. phospholipid bilayer
Term
fluid mosaic model
Definition
model stating that the phospholipid bilayer is like a mosaic because of the different proteins dispersed unevenly throughout and they have a fluid characteristic because they do not stay in position but move around within the layer
Term
betacyanin
Definition
a reddish pigment found in beets that is localized almost entirely in the large central vacuole of its cells
Term
tonoplast
Definition
the vacuolar membrane
Term
effects of temperature on membranes
Definition
high temps-violent molecular collisions destroy membrane as barrier to diffusion
low temps-ruptures membranes
Term
effects of organic solvent stress on membranes
Definition
dissolve a membrane's lipids
Ex. acetone, methanol
Term
enzymes
Definition
proteins that control reactions in cells by acting as biocatalysts and accelerating metabolic reactions to biologically useful rates by lowering activation energy
Term
substrate
Definition
reacting molecules that enzymes bind to to form an enzyme-substrate complex
Term
transition state
Definition
formed when the enzyme-substrate complex stresses or distorts chemical bonds and causes the substrate to become more reactive and the metabolic reaction to accelerate
Term
energy of activation
Definition
the energy needed to form the transition state, lowered by an enzyme
Term
enzyme's active site
Definition
the site of attachment and the surrounding parts of the enzyme that stress the substrate's bonds
Term
denature
Definition
the destruction of an enzyme's effectiveness by altering the active site and slowing down the reaction rate due to a structural change in the enzyme
Term
optimal conditions
Definition
the range of values for environmental factors such as temp and pH at which an enzyme functions best
Term
effect of temp on reactions/enzymes
Definition
for every 10 degrees temp rises reaction doubles, extreme temp denatures enzymes
Term
catechol oxidase
Definition
a plant enzyme that can be used to investigate the effects of temperature on enzyme activity
Term
effects of pH on enzymes
Definition
extreme pH denatures enzymes, optimal pH=7, exceptions are pepsin & trypsin
Term
catalase
Definition
an enzyme in plants and animals that speeds up the breakdown of hydrogen peroxide and can be used to investigate the effects of pH on enzymes
Term
peroxidase
Definition
an enzyme in plants (such as turnips) and some bacteria that converts toxic hydrogen peroxide to water and oxygen
Term
competitive inhibition
Definition
inhibitions that occur from molecules that are structurally similar to a substrate and compete for a position at the active site of an enzyme, making the enzyme unable to bind with the substrate
Term
buffer
Definition
a compound that keeps pH from changing
Term
cellular respiration
Definition
a way cells harvest energy from food, a catabolic pathway for the production of adenosine triphosphate (ATP), includes glycolysis, formation of acetyl CoA, citric acid cycle, and ETC/chemiosmosis
Term
glycolysis
Definition
the first stage of cellular respiration, glucose is oxidized to pyruvate via a set of chemical reactions
Term
citric acid cycle
Definition
also known as tricarboxylic acid cycle or Krebs cycle, pyruvate is oxidized to carbon dioxide via chemical reactions
Term
aerobes
Definition
organisms that use oxygen for respiration beyond glycolysis
Term
electron transport chain
Definition
generates proton gradients from energy stored in reduced NAD and related compounds to form large amounts of ATP, oxygen is the final electron acceptor
Term
fermentation
Definition
a process used by anaerobes in which pyruvate from glycolysis is reduced to either carbon dioxide and ethanol or lactic acid
Term
pyruvate
Definition
a product of glycolysis; pyruvate is reduced to ethanol or lactic acid during anaerobic fermentation
Term
magnesium sulfate
Definition
provides Mg2+, a cofactor that activates some enzymes of glycolysis
Term
sodium fluoride
Definition
an inhibitor of some enzymes of glycolysis
Term
glucose
Definition
a common organic molecule used as an energy source for respiration
Term
pH
Definition
a measure of the acidic or basic properties of a solution
Term
photosynthesis
Definition
a complex chemical process that converts radiant energy (light) to chemical energy (sugar), 2 stages-light reactions and dark reactions (Calvin cycle)
Term
pigment
Definition
a substance that absorbs light
Term
primary photosynthetic pigments
Definition
chlorophyll a, b, and accessory pigments (carotenes and xanthophylls)
Term
paper chromatography
Definition
a technique for separating dissolved compounds such as chlorophyll, carotene, and xanthophyll
Term
Rf
Definition
relationship of the distance moved by a pigment to the distance moved by the solvent front
Term
spectroscope
Definition
an instrument that separates white light into its component colors
Term
fluorescence
Definition
the release of light energy as an excited electron falls back into its original orbital and emits a photon of red light
Term
phenol red
Definition
a pH indicator that turns yellow in an acidic solution and becomes red in a neutral to basic solution
Term
thylakoids
Definition
photosynthetic membranes located within a chloroplast organelle
Term
grana
Definition
stacks of thylakoids
Term
lamellae
Definition
hold the grana in place
Term
stroma
Definition
a semiliquid inside the chloroplast that contains the enzymes that catalyze the light independent reactions of photosynthesis
Term
cell cycle
Definition
repeating set of events in which cells grow, have specific functions, and replicate
Term
mitosis
Definition
replication and division of the nucleus of a eukaryotic cell in preparation for cytokinesis
Term
cytokinesis
Definition
the division of the cell and cytoplasm into halves that each contain a nucleus
Term
interphase
Definition
part of the cell cycle that does not include mitosis, includes cytokinesis, gap 1, synthesis, and gap 2 phases
Term
chromatids
Definition
chromosomal DNA strands
Term
centromere
Definition
the structure on a chromosome that attaches the sister chromatids
Term
centrosomes
Definition
two microtubule organizing centers that contain cylinders of microtubules called centrioles
Term
polar fibers
Definition
the axis of proteinaceous microtubles between the pairs of centrioles
Term
mitotic spindle
Definition
the bridge of microtubules that extends between centrioles that are at opposite ends of the cell
Term
kinetochore fibers
Definition
fibers that attach to each chromosome's kinetochore
Term
kinetochore
Definition
a complex of proteins that binds to the centromere of a chromosome
Term
aster
Definition
the arrangement of microtubules radiating from a centriole
Term
prophase of mitosis
Definition
mitotic spindle fibers begin to form, polar and kinetochore fibers comprise the mitotic spindle, chromosomes continue to condense
Term
metaphase of mitosis
Definition
the chromosomes align on a plane in the center of the cell
Term
anaphase of mitosis
Definition
the sister chromatids seperate
Term
telophase of mitosis
Definition
mitotic apparatus disassembles
Term
cleavage furrow
Definition
a process in cytokinesis that begins on the periphery of an animal cell, pinches inward, and eventually divides the cytoplasm into 2 cells
Term
blastula
Definition
early embryonic stage of a vertebrate, consists of a sphere of 25-100 cells
Term
meristems
Definition
localized areas of rapid cell division due to active growth at the root tips
Term
cell plate
Definition
forms during cytokinesis of plant cells, is a partition perpendicular to the axis of the spindle apparatus
Term
homologous chromosomes
Definition
the two chromosomes of a pair, each homologue has same site (loci) for the same genes, although alleles may be different
Term
haploid
Definition
only one chromosome of each homologous pair
Term
meiosis
Definition
produces haploid daughter nuclei, referred to as "reduction division"
Term
synapsis
Definition
pairing of homologous chromosomes
Term
crossing-over
Definition
the exchange of genetic material/alleles by homologous chromatids to produce new genetic combinations
Term
meiosis 1
Definition
separates homologous chromosomes
Term
meiosis 2
Definition
separates chromatids composing each chromosome
Term
gametes
Definition
reproductive cells with haploid nuclei resulting from meiosis
Term
gametogenesis
Definition
the formation of gametes
Term
spermatogenesis
Definition
formation of sperm cells
Term
oogenesis
Definition
formation of egg cells
Term
seminiferous tubules
Definition
tightly coiled tubes that make up male testes
Term
spermatogonia
Definition
diploid cells packed against the inner walls of seminiferous tubules that are constantly replicating mitotically during the life of males
Term
primary spermatocytes
Definition
daughter cells of spermatogonia that move inward toward the lumen of the tubule and begin meiosis
Term
secondary spermatocytes
Definition
two haploid cells, each with double-stranded DNA, formed from meiosis 1 of a primary spermatocyte
Term
spermatids
Definition
2 haploid cells produced by the separating of the strands of each chromosome from the secondary spermatocytes through Meiosis 2
Term
sperm cells
Definition
mature spermatids
Term
oocytes
Definition
cells of the ovary that produce female gametes
Term
primary oocytes
Definition
cells that are produced by the mitosis of oogonia
Term
ovulation
Definition
the release of the oocyte from the ovary
Term
follicular cells
Definition
cells that surround and support primary oocytes
Term
secondary oocyte
Definition
produced by meiosis 1 of a primary oocyte
Term
corpus luteum
Definition
formed by the follicle cells that remain after ovulation, produces hormones that prepare the uterus for potential arrival of a fertilized egg
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