bio lab final

Question 1

cellular respiration

Answer 1

release of energy from glucose to synthesize ATP

Question 2

aerobic respiration requires _______ and releases ________

Answer 2

O2; CO2

Question 3

3 phases of cellular respiration + where they occur

Answer 3

1. glycolysis - occurs in cytoplasm
2. citric acid cycle (Krebs cycle) - occurs in mitochondrial matrix
3. electron transport chain - occurs in inner membrane of mitochondria

Question 4

ethanol fermentation (aka anaerobic respiration)

Answer 4

• takes place in the cytoplasm of cell
• in yeasts, pyruvate is reduced to ethyl alcohol by fermentation and CO2

other not bolded info:
- fermentation yields only 2 ATP molecules and does not require O2

• glucose is partially broken down, therefore, most of the potential energy stored in glucose has not been released

Question 5

sequence for fermentation (anaerobic respiration)

Answer 5

glucose –> glycolysis –> pyruvate –> CO2, lactate, or ethanol

Question 6

photosynthesis description

Answer 6

• converts solar energy into chemical energy of carbohydrates
• CO2 and H2O diffuse into cells and enter chloroplast organelles
• during light reactions, pigments within thylakoid membranes absorb solar energy, water is split and oxygen released

Question 7

reactants and products of photosynthesis (the equation)

Answer 7

6CO2 + 6H2O –> C6H12O6 + 6O2

Question 8

how did we test the hypothesis that leaves contain various pigments that absorb solar energy of different colors of light?

Answer 8

• used chromatography to separate pigments located in leaves

Question 9

how does chromatography work?

Answer 9

• separates molecules from each other on basis of their solubility in particular solvents
• solvents are nonpolar- as nonpolar solvent moves up chromatography paper, the pigment moves along with it
• the more nonpolar a pigment, the more soluble it is in a nonpolar solvent and faster and further it proceeds up chromatography paper

Question 10

what colors does chlorophyll absorb and what colors does it reflect?

Answer 10

chlorophylls absorb predominantly violet-blue and orange-red light and reflect green light

(why plants are green)

Question 11

mitosis vs meiosis (definition)

Answer 11

mitosis: occurs in somatic cells (body cells that undergo cell division continuously to replace dead and damaged cells
- ex. fat cells, skin cells, blood cells, etc.

meiosis: process by which sex cells (gametes) are produced in organism that require sexual reproduction
- male gonads (testes) produce sperm (male gametes)
- female gonads (ovaries) produce oocytes (female gametes)

Question 12

the process of mitosis duplicates and divides 2 cells _________

Answer 12

equally

Question 13

stages of the cell cycle

Answer 13

1. interphase - divided into 3 stages:
   
   • G1 (stage before DNA synthesis)
   • S (DNA synthesis)
   • G2 (stage after DNA synthesis)
2. mitotic stage:
   - mitosis: division of the nucleus
   - cytokinesis: division of the cytoplasm

Question 14

what happens in the S phase

Answer 14

DNA replication (synthesis) occurs

• after DNA replication, each chromosomes has gone from 1 DNA molecule to 2 DNA molecules, called sister chromatids

Question 15

where are sister chromatids held together?

Answer 15

at a centromere

other info:
- creates a short arm and a long arm at the chromatid

Question 16

list the stages of mitosis and a brief description of each

Answer 16

1. interphase: chromosomes have already replicated during interphase
2. prophase: sister chromatids condense and spindle starts to form. nuclear membrane begins to dissociate into vesicles
3. metaphase: sister chromatids align along the metaphase plate
4. anaphase: sister chromatids separate and individual chromosomes move toward poles as kinetochore microtubules shorten. polar microtubules lengthen and push poles apart.
5. telophase and cytokinesis: chromosomes decondense and nuclear membranes re-form. cleavage furrow separates the 2 cells.

Question 17

how is mitosis different in plant cells?

Answer 17

• plant cells do not have centrioles and asters; plant cells do not have centrosomes
• cytokinesis is different in plants: membrane vesicles derived from Golgi apparatus migrate to the center of cell and form a cell plate (the location of a new plasma membrane for each daughter cell)

Question 18

in meiosis, chromosome number is __________

and how many daughter cells in the end?

Answer 18

reduced by half

• end with 4 haploid (1n) daughter cells

Question 19

crossing over in meiosis I

Answer 19

• homologues line up side by side in a process called synapsis during prophase I
• crossing over occurs: the exchange of genetic material between nonvoter chromatids of homologues

Question 20

phenotype vs genotype

Answer 20

phenotype: individual’s physical appearance

genotype: genetic makeup, alleles responsible for a given trait

Question 21

heterozygous vs homozygous in mendelian inhertiance patterns

Answer 21

• individual with 2 identical alleles is homozygous for the gene (GG or gg)
• individual with 2 different alleles is heterozygous for that gene (Gg)

Question 22

monohybrid cross + phenotypic and genotypic ratio

Answer 22

monohybrid: a single pair of alleles is involved in one-trait cross

phenotypic ratio- 3:1

genotypic ratio - 1:2:1

Question 23

law of segregation

Answer 23

pair of alleles segregate from each other during meiosis so that only one allele is present in each gamete

• segregation of alleles corresponds to distribution of homologous chromosomes to different gametes in meiosis

Question 24

dihybrid cross + phenotypic ratio

Answer 24

• two traits are crossed - involves pair of alleles
• 2 hybrids (AaBb) mate = phenotypic ratio of 9:3:3:1
• 4 possible phenotypes
• determines whether 2 traits are transmitted to offspring as a package or independently

Question 25

law of independent assortment

Answer 25

each pair of alleles segregate independently of any other pair of alleles during gamete formation *the allele a gamete receives for one gene does not influence the allele received for another gene* (on the slide for dihybrid cross)

Question 26

how to determine gametes for dihybrid cross

Answer 26

FOIL First allele from each trait Outer allele from each trait Inner allele from each trait Last allele from each trait

Question 27

each nucleotide is composed of...

Answer 27

- phosphate group - sugar molecule (deoxyribose) - 1 of 4 nitrogenous bases

Question 28

describe the structure of DNA

Answer 28

- polymer of nucleotides consists of 2 long chains of nucleotides wound together in a double helix - joined by *hydrogen bonds* between complementary nitrogenous bases in opposite strands - Adenine (A) and Thymine (T) - Cytosine (C) and Guanine (G) phosphate and sugar parts of nucleotides form backbone of each strand in DNA

Question 29

order of what influences the characteristics of an organism

Answer 29

*sequence of nucleotides* in DNA of gene = determines *sequence of amino acids* in a protein = determines *the structure and function* of protein = influences the *characteristics* or traits of the organism

Question 30

describe the steps of DNA extraction

Answer 30

- solution of DNA sample and reagents used are kept cold in order to stabilize and protect DNA from breakage (preserves fragile hydrogen bonds = strands stabilized) steps for DNA extraction: 1. **lysis**: lysis bugger and heat disrupt cell membrane phospholipids releasing membrane proteins and freeing DNA into solution 2. **precipitation**: separate DNA from protein and other cell components using papain (protease), digests histones (proteins that DNA wraps around), salt in papain neutralizes negative charges on phosphate groups making molecule less hydrophilic and less soluble in water, heat denatures cell's enzymes to protect DNA from enzymatic degradation 3. **purification**: isolate concentrated DNA using cold ethanol, reduces temperature and causes DNA to precipitate (solidifies) while preserving H-bonds, DNA is polar but ethanol has a large nonpolar component, making DNA less soluble in ethanol

Question 31

describe the DNA extraction steps we performed to estimate concentration of DNA in the sample

Answer 31

1. estimate amount of DNA present in sample by diphenylamine method using UV spectrophometer 2. record absorbance at 595 nm 3. use absorbance of known solutions to estimate concentration of DNA in sample

Question 32

Diphenylamine method

Answer 32

- acidic conditions convert deoxypentose (from purine nucleotides) to β hydroxyl leavulinic aldehyde - diphenylamine reacts with β hydroxyl leavulinic aldehyde to form a blue colored solution - absorbance measured using a spectrophotometer at 595 nm (amount of UV radiation absorbed/intensity of blue color is directly proportional to concentration of DNA in sample)