bio lab final Flashcards
cellular respiration
release of energy from glucose to synthesize ATP
aerobic respiration requires _______ and releases ________
O2; CO2
3 phases of cellular respiration + where they occur
- glycolysis - occurs in cytoplasm
- citric acid cycle (Krebs cycle) - occurs in mitochondrial matrix
- electron transport chain - occurs in inner membrane of mitochondria
ethanol fermentation (aka anaerobic respiration)
- 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
sequence for fermentation (anaerobic respiration)
glucose –> glycolysis –> pyruvate –> CO2, lactate, or ethanol
photosynthesis description
- 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
reactants and products of photosynthesis (the equation)
6CO2 + 6H2O –> C6H12O6 + 6O2
how did we test the hypothesis that leaves contain various pigments that absorb solar energy of different colors of light?
- used chromatography to separate pigments located in leaves
how does chromatography work?
- 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
what colors does chlorophyll absorb and what colors does it reflect?
chlorophylls absorb predominantly violet-blue and orange-red light and reflect green light
(why plants are green)
mitosis vs meiosis (definition)
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)
the process of mitosis duplicates and divides 2 cells _________
equally
stages of the cell cycle
-
interphase - divided into 3 stages:
- G1 (stage before DNA synthesis)
- S (DNA synthesis)
- G2 (stage after DNA synthesis)
-
mitotic stage:
- mitosis: division of the nucleus
- cytokinesis: division of the cytoplasm
what happens in the S phase
DNA replication (synthesis) occurs
- after DNA replication, each chromosomes has gone from 1 DNA molecule to 2 DNA molecules, called sister chromatids
where are sister chromatids held together?
at a centromere
other info:
- creates a short arm and a long arm at the chromatid
list the stages of mitosis and a brief description of each
- interphase: chromosomes have already replicated during interphase
- prophase: sister chromatids condense and spindle starts to form. nuclear membrane begins to dissociate into vesicles
- metaphase: sister chromatids align along the metaphase plate
- anaphase: sister chromatids separate and individual chromosomes move toward poles as kinetochore microtubules shorten. polar microtubules lengthen and push poles apart.
- telophase and cytokinesis: chromosomes decondense and nuclear membranes re-form. cleavage furrow separates the 2 cells.
how is mitosis different in plant cells?
- 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)
in meiosis, chromosome number is __________
and how many daughter cells in the end?
reduced by half
- end with 4 haploid (1n) daughter cells
crossing over in meiosis I
- 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
phenotype vs genotype
phenotype: individual’s physical appearance
genotype: genetic makeup, alleles responsible for a given trait
heterozygous vs homozygous in mendelian inhertiance patterns
- individual with 2 identical alleles is homozygous for the gene (GG or gg)
- individual with 2 different alleles is heterozygous for that gene (Gg)
monohybrid cross + phenotypic and genotypic ratio
monohybrid: a single pair of alleles is involved in one-trait cross
phenotypic ratio- 3:1
genotypic ratio - 1:2:1
law of segregation
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
dihybrid cross + phenotypic ratio
- 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
law of independent assortment
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)
how to determine gametes for dihybrid cross
FOIL
First allele from each trait
Outer allele from each trait
Inner allele from each trait
Last allele from each trait
each nucleotide is composed of…
- phosphate group
- sugar molecule (deoxyribose)
- 1 of 4 nitrogenous bases
describe the structure of DNA
- 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
order of what influences the characteristics of an organism
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
describe the steps of DNA extraction
- 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
- 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
- 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
describe the DNA extraction steps we performed to estimate concentration of DNA in the sample
- estimate amount of DNA present in sample by diphenylamine method using UV spectrophometer
- record absorbance at 595 nm
- use absorbance of known solutions to estimate concentration of DNA in sample
Diphenylamine method
- 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)
