Biology 141 Lab Exam #2

Cytokinesis

-BEGINNING OF CYTOPLASMIC DIVISION -sometimes telophase results in cytokinesis and 2 separate cells (not in fungi) -cleavage furrow forms at equator and pinches the parent cell cytoplasm in 2 using ACTIN and MYOSIN (in muscle cells) to form the cleavage furrow and contractile ring: animal, fungi, slime mold -cell plate forms in plant cells when membrane-bound vesicles migrate to center of equatorial plane and fuse to form cell plate. They extend across cell and divide cytoplasm in 2. Cell wall materials in vesicles are released into the space between membranes of cell plate forming new cell wall.

telomeres

-DNA sequences on the ends of chromosomes that become shorter during every mitotic cycle of somatic cells -W/out telomeres, important genes at the ends would be lost in mitosis -limits the number of mitotic cycles per cell -if telomeres fail to shorten - uncontrolled mitosis

cellular respiration

-aerobic (utilizing oxygen) cellular process that releases the energy in glucose to synthesize ATP -involve oxidation/reduction reactions -max 32 ATP

Anaphase

-after centromere splits, sister chromatids separate and move towards opposite poles -NOW chromosomes -ends when chromosomes reach poles

types of fermentation

-alcoholic fermentation: plants and fungi (yeast!) convert pyruvate to acetaldehyde by releasing CO2, acetaldehyde is reduced to ethyl alcohol (2 carbon molecule) by oxidizing 2 NADH to NAD+ -lactic acid fermentation: animals, certain fungi, and bacteria reduce pyruvate to lactate -both regenerate NAD+

fermentation

-anaerobic (in absence of oxygen) cellular process that releases the energy in glucose to synthesize ATP -involve oxidation/reduction reactions -involves glycolysis but not citric acid cycle and ETC (inhibited at low O2 levels) -only 2 ATP -in the cytoplasm of cell

cellular respiration experiment #2

-can use additional substrates (glucose, fructose, maltose, starch, saccharin, etc) inhibitors (spices like turmeric containing curcumin) -rotenone: insecticide inhibiting e- flow in ETC -oligomycin: antibiotic inhibiting ATP synthesis -antimycin: antibiotic inhbiting transfer of e- to O2 -malonate: blocks conversion of succinate to malate -pH ranges? temperature ranges? - optimum

interphase

-cell performs specific functions (liver: bile, intestine: absorb nutrients, pancreas: secrete enzymes, skin: keratin) -G1: begins with 1/2 as much cytoplasm as before cell division; nuclear envelope to surround nucleus, nucleolus, chromatin, outside nucleus is centrosome

Prometaphase

-centrioles at poles of cell -chromosomes continue condensing -nuclear envelope BREAKS DOWN -kinetochores: some spindle fibers become associated with chromosomes at these protein structures (each sister chromatid has kinetochore at its centromere); these spindle microtubules extend from chromosomes to centrosomes -push and pull of spindle fibers on chromosomes moves them to equator

Prophase

-chromosomes begin to coil and condense (visible) -centrioles continue moving to opposite poles -spindle made of microtubules (tubulin) begins to form between centrioles -nucleoli begin to disappear -nuclear envelope INTACT

difference between blank and control

-control is a tube with no succinate and no inhibitor as a part of the experimental design -in this experiment Tube 1 is control

Redox reactions

-defined in terms of electron transfers -oxidation is loss of electrons -reduction is gain of electrons -2 H2 (like 2 e- and 2 H+) are removed from glucose (oxidation) and are transferred to a coenzyme NAD+ (nicotinamide adenine dinucleotide) - reducing the compound to NADH -NAD+ is the oxidizing agent that is reduced to NADH by 2 e- and 1 H+

genes

-discrete units of hereditary information consisting of duplicated DNA (deoxyribonucleic acid) -found in chromosomes in nuclei of eukaryotic cells

cell cycle

-events from beginning of one cell division to beginning of next -2 phases: interphase and mitotic (M) phase -interphase: G1, S, G2 -G1: parts of cytosol increase/prep enzymes -S: DNA synthesis/chromosome replication -G2: proteins and material prep for mitosis -M phase: prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis

3 stages of respiration

-glycolysis in cytoplasm (net 2 ATP, 2 NADH) -citric acid cycle in mitochondria (CO2, ATP, NADH, FADH2): 8 steps catalyzed by specific enzymes releasing CO2, H+, e- which are passed to NAD+ and FAD (flavin adenine dinucleotide) -ETC and its enzymes in mitochondria (ATP, water): NADH and FADH2 carry electrons to ETC, where electrons pass along chain to final e- acceptor O2. ATP and water produced.

human chromosomes

-human leukocytes are isolated from blood and cultured to inhibit spindle formation in mitosis; cells begin mitosis and chromosomes are condensed in prometaphase/metaphase -46 chromosomes , 23 pairs -cytogeneticists can detect chromosomes abnormalities that can lead to mental retardation -down's syndrome: trisomy 21 so 47 total chromosomes -each chromosome is duplicated (2 sister chromatids); and ABNORMALITIES IN BANDING PATTERNS of sister chromatids INDICATE RETARDATION

meiosis

-in prep for sexual reproduction, nuclear division of certain cells in ovaries, testes, sporangia divide twice, but chromosomes only replicate once -egg, sperm, spores are formed -contributes to genetic variation important in sexual reproduction

energy flow

-light energy from sun is transformed to chemical energy in photosynthesis -chemical energy is used to synthesize glucose and oxygen from CO2 and H2O -energy stored in plant organic molecules used by plant or consumers -energy in organic molecules is released to form ATP in respiration in plants, animals, etc.

somatic cells and single-celled organisms

-nuclear division by MITOSIS into 2 daughter nuclei (have the same chromosome # and genes as parent) -function of mitosis: new cells for tissue maintenance & repair, asexual reproduction, growth, development -epidermis skin cells continuously replaced by mitosis -yeast and amoeba reproduce asexually to make genetically identical clones -LOCATION: meristem tissue actively dividing plant tissue in root/bud -initial cell can be haploid or diploid -cancerous cells are uncontrolled mitotic and cell division

mitosis and cytokinesis in plants

-onion root tip cells -differences include how plants have no centrioles - instead bundles of microtubules that converge toward poles at ends of spindle; cell walls form differently -DIAGRAM of longitudinal section (zone of cell division) -root cap protects root tip while growing (zone of cell division - cells produced mature and differentiate) -INTERPHASE: nuclear envelope, nucleoli visible, chromatin mass (chromosomes being replicated) -PROPHASE: chromosomes begin to coil, spindle forms, nucleoli maybe, nuclear envelope -PROMETAPHASE: chromosomes thick and short (duplicated sister chromatids w centromere); nuclear envelope DISINTEGRATE; nucleoli GONE; chromosomes moving -METAPHASE: chromosomes on equator (arms extend randomly; spindle fibers attached to kinetochores of centromeres and extending -ANAPHASE: splitting of centromeres (each single chromosome draw to opposite poles) -TELOPHASE: chromosomes reached opposite poles, nuclear envelope RE-FORMS, nucleoli REAPPEAR, chromosomes uncoil -CYTOKINESIS: formation of cell plate

mitosis and cytokinesis in animal cells

-plant chromosomes are generally larger than animal -animals have cleavage furrow, centrosome with centrioles and asters -whitefish blastula cells (early embryonic stage shows cells rapidly dividing) -asters: array of microtubules surrounding each centriole pair at the poles of the spindle -centrioles: small dots at the poles around which the microtubules of the spindle and asters radiate -DIAGRAMS for ALL STAGES! (pink nucleus interphase, purple chromosomes)

experimental design techniques

-research question -formulate testable hypothesis -summarize essential elements of experiment -predict results of experiment based on hypothesis (if/then statement) -outline procedure to be used: modify original procedure, create table for tubes, check for replicates, levels of treatment, controls, time intervals, total volume of exp tubes, exp conditions, glassware -perform experiment: make observations/collect data -record results in data table thoroughly -prepare discussion: review prediction (did it correspond), review hypothesis (support/falsify?); explain problems w procedure/questionable results, improvements, summarize conclusion from results -report results to class (persuade that results support conclusion)

Telophase

-spindle breaks down -chromosomes begin to uncoil -nucleoli REAPPEAR -nuclear envelope FORMS -ends when nuclear envelope is complete -END OF NUCLEAR DIVISION

Metaphase

-static phase -centromeres (duplicated chromosomes) lying on equator or metaphase plate -ends when centromere b/w 2 sister chromatids splits

chromosomes

-structural proteins in chromosomes (histones) organize DNA and help with condensation -cells divide after chromosomes and genes are duplicated and passed to daughter cells -single-celled organisms divide for reproduction -multicellular organisms have reproductive cells (sperm/egg) and somatic cells that divide for growth and replacement

results

-transmittance increased more rapidly in Tube 3 because there was the highest amount of succinate (reactant) for the reaction -other IV that could be investigated is increasing temperature, pH, inhibitors

cellular respiration experiment #1

-using isolated matrix mitochondrial suspension from pulverized lima beans (on ice to prevent enzyme degradation so citric acid cycle can continue; sucrose added for osmotic balance) -SPECIFIC STEP: citric acid cycle is enzyme catalyzed conversion of succinate to fumarate (succinate loses 2H+ and 2e- to FAD (reducing it to FADH2) using a dehydrogenase and creating fumarate) -the step is utilized to find rate of respiration -add indicator DPIP (di-chlorophenol-indophenol), an e- acceptor that intercepts H+ and e- released from succinate and changes DPIP from oxidized to reduced state (blue in oxidized to colorless reduced) -using this color change to measure respiration rate -a SPECTROPHOTOMETER measures the proportion of light of different wavelengths absorbed by pigment (specific wavelength of light passes through pigment solution and measures light transmitted, or absorbed by DPIP) -as DPIP changes from blue to clear - aerobic respiration increases, less light is absorbed and more light is transmitted through solution, so transmittance reading/percentage increases -tests changing the amount of succinate effect on cellular respiration rate

humans

2n = 46 n = 23

diploid cell with 4 chromosomes

2n; 2 homologous pairs of chromosomes

pyruvate

3 carbon molecule product of glycolysis

chromosome

DNA in condensed form with genes and protein (easier to find and express)

S

DNA synthesis continues until duplication of chromosomes for DNA replication; each strand of duplicated chromosome is called sister chromatid; synthesis of chromosomal proteins;

prediction

If increasing succinate concentration will increase rate of cellular respiration, then DPIP will turn blue to colorless faster and percent transmittance will increase.

hypothesis

Increasing succinate concentration will increase rate of cellular respiration

ATP

adenosine triphosphate; the energy in ATP is used to perform cellular work

cytokinesis

after both mitosis and meiosis (after nuclear division), the cytoplasm divides

aster

array of microtubules connected to centriole; only in animals

ALL LIVING ORGANISMS:

bacteria, protists, plants, animals, etc. produce ATP in respiration or fermentation and use ATP in metabolism

G2

cell prepares for mitosis; enzymes and proteins necessary for nuclear and cell division synthesized; centriole pairs moved to opposite poles of nucleus

chromatin

chromosomes in decondensed state as a mass of DNA and protein

spindle

fibrous, rounded structure tapering at end forms between centrioles

centrosomes

formation of spindle begins here in MTOC (microtubule organizing center); only in animals; contains pair of centrioles; organization center for microtubules

chromatid

half a replicated chromosome: after DNA replication, 2 strands, single centromere moves as 1 unit

centromere

holds 2 sister chromatids, microtubular structures that form at centromere attach to microtubules of spindle kinetochore

G1

mass of chromatin; 1 centriole pair outside nucleus at right angles; cytoplasmic mass increases; proteins synthesized; new organelles form (mitochondria/chloroplasts divide in 2); nucleoli (dark round bodies) are VISIBLE centriole duplication in late G1, early S

haploid

n; only have 1 of each homologous pair of chromosomes

equator

plane where chromosomes line up in metaphase

centrioles

replicated in S, come in pairs, only in animals

homologous chromosomes

same length; same centromere position; genes for same characters in same position (locus) on chromosome - have potential to have different alleles for genes

cuvette

special test tube doesn't interfere w/ wavelength of light

procedure

spectrophotometer: CHECK PICTURE -set 600 nm - wavelength absorbed by DPIP -set 0% transmittance w/ no cuvette inside -Blank, 1, 2, 3 cuvettes -Blank: phosphate buffer (water), mitochondrial suspension (provides enzymes), succinate (reactant), NO DPIP - adjust light control until it reads 100% transmittance w the blank - corrects for differences in transmittance due to mitochondrial solution and standardizes before each set -1, 2, 3: phosphate buffer, DPIP, mitochondrial suspension, and succinate ADDED LAST or reaction will start too soon - parafilm, invert, wipe, place and record transmittance -IV: concentration of succinate -DV: % transmittance of light through DPIP every 5 minutes for 30 minutes -legend: IV (concentrations)

NADH

transfers electrons to ETC; transfer of electrons from one molecule to another releases energy which is used to synthesize ATP