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Biology 30 Flashcards

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1
Q

what is the chromosome number in somatic (body) and autosomal (sex) cells? why is is significant? what is polyploidy?

A

*n indicates chromosome number
somatic/diploid cells -> 2n = 46
autosomal/haploid cells -> n = 23

polyploidy is when there is more then 2n chromosomes in the somatic cells of an organism (4n = 12, sex cells will be n = 3)

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2
Q

what is the cell cycle? what happens at each stage of the cell cycle?

A

Interphase: G1 - growth, S - DNA synthesis, G2 - growth and preparation for mitosis
Mitosis: PMAT
Cytokinesis: cell divides

Cell specialization: Cells leave the cell cycle – do not continue to divide. (like red blood cells)

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3
Q

what is the process of meiosis? why is it neccassary?

A

prophase 1: homologous chromosomes pair up, crossing over between tetrads, spindle fibre form
metaphase 1: tetrads randomly line up a long the plate
anaphase 1: homologous chromosomes split up and go to opposite ends
telophase 1: cell splits into 2 haploid cells, nuclear envelope forms, chromosomes uncondense

prophase 2: new spindle forms, sister chromatids recondense, nuclear envelope fragments
metaphase 2: sister chromatids line up at the plate
anaphase 2: sister chromatids seperate
telophase 2: chromosomes arrive at the pole and decondense, 4 haploid cells

necessary because it maintains chromosome number in all individuals and results in genetic variation (crossing over)

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4
Q

what is the difference between mitosis and meiosis?

A

Mitosis –> somatic cells, growth repair and maintenance, 1 diploid cell to 2 diploid cells which are identical to parent cell, 1 division

Meiosis –> gonads, make gametes, result in variation, 1 diploid cell to 4 haploid cell, 2 divisions, synapsis (pairing of homologous chromosomes), crossing over, segregation, tetrads

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5
Q

what happens during crossing over? what are linked genes?

A

during prophase 1 of meiosis the homologous chromosomes will exchange genetic information, or segments of DNA. Crossing over occurs between genes that are further a part on the chromosome.
linked genes are genes that are found on the same chromosome

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6
Q

what is nondisjunction?

A

abnormal seperation in meiosis and can occur 2 times

anaphase 1: homologous chromosomes move to the same pole, results in 2 gametes having an extra chromosome and 2 gametes having 1 less chromosome

anaphase 2: sister chromatids move to the same pole, results in 1 gamete having an extra chromosome, 1 gamete having one less chromosome and 2 healthy gametes

Trisonomy - Down syndrome (21), Klienfelters (XXY), Jacobs (XYY) Edward and Patau (18,13) , one extra chromosome
Monosomy - turners syndrome (23, XO), one less chromosome

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7
Q

what is the difference between fraternal and identical twins?

A

identical: 1 egg fertilized by 1 sperm, During mitosis a single cell
breaks free and a second embryo develops, Same sex, blood type and genetic make up

fraternal: 2 different eggs and 2 different sperm, Do not have the same genetic make up (genes), similar to regular siblings but share uterus

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8
Q

what is the plant life cycle in terms of ploidy?

A

zygote (2n) -> mature sporophyte (2n) -> meiosis -> spores (n) -> mitosis -> male and female gametophyte (n) -> gametes (n) -> fertalization -> zygote (2n)

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9
Q

what is the animal life cycle in terms of ploidy?

A

zygote (2n) -> mitosis -> animal body (2n) -> meiosis -> gametes (n) -> fertalization -> zygote (2n)

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10
Q

how is genetic information contained in the sequence of bases in DNA molecules in chromosomes?

A

nucleotide is functional unit (phosphate-sugar-nitrogen base)
sequence of DNA bases code for a protein monomers (amino acids) The information stored in the order of bases is organized into genes: each gene contains information for making a functional product.
Noncoding - DNA codon - mRNA codon - tRNA codon carrying amino acids

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11
Q

how do DNA molecules replicate themselves?

A

occurs during cell division.

  1. helicase enzyme unzips and unwinds double helicase DNA strand by breaking H bonds creating a “Y” shape at the replication fork
  2. primase enzyme binds to the exposed strands which then causes free floating RNA bases to bind to the complimentary DNA bases to make a primer
  3. DNA polymerease enzyme binds to the primer and causes DNA bases to bind to the original DNA strands
  4. once the strand is complete the RNA primers will leave and the gaps will be filled with more DNA bases and then 2 new strands are made each with half of the original strand
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12
Q

how is genetic information is transcribed into sequences of bases in RNA molecules?

A
  1. RNA polymerase binds to a segment of a DNA strand and unwinds and unzips it
  2. RNA base pairs bind to the DNA and make the mRNA molecule until it reads stop (and A on the DNA binds to Uracil on RNA)
  3. mRNA strand leaves the nucleus
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13
Q

how is genetic information translated into sequences of amino acids in proteins?

A
  1. tRNA picks up amino acid and joins with mRNA
  2. The ribosome moves down the mRNA and another tRNA brings the next amino acid and releases it after reading the codon
  3. When mRNA codon reads “stop” the polypeptide (amino acid chain) is released and sent to the gogli apparatus
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14
Q

how do restriction enzymes cut DNA molecules into smaller fragments? how do ligases reassemble them?

A

The cuts are always made at specific nucleotide sequences . Different restriction enzymes recognise and cut different DNA sequences.
It comes into contact with a DNA sequence with a shape that matches a part of the enzyme , called the restriction site. It then wraps around the DNA and causes a break in both the strands of the DNA molecule leaving a sticky end
Each restriction enzymes recognises a different and specific recognition site or DNA sequence. Recognition sites are usually only 4 - 8 nucleotides long. ex. Eco RI

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15
Q

how can cells be transformed by inserting new DNA sequences into their genomes?

A
  1. A bacterial plasmid isopened using a restriction enzyme
  2. Isolation of the desired gene using the same Restriction Enzyme
  3. Both DNA samples are combined in a petri dish or a test tube.
  4. Ligase is added to glue DNA together.
  5. Recombined plasmid inserted back into E. coli bacterial cell. Bacteria divides, mass producing the desired product, ex. insulin
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16
Q

how does a random change (mutation) in the sequence of bases result in abnormalities?

A 
point mutations; Arise from mistakes in replication which change the genetic code. An incorrect mRNA built using altered DNA as
template. 
Sub- swap of one base pair for another
Add- extra base pairs FRAMESHIFT
Delete- removal of base pairs FRAMESHIFT
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17
Q

how are base sequences in nucleic acids that are contained in the nucleus, mitochondrion and chloroplast all inherited?

A

nuclear DNA: in nucleus, long strands of chromatin then chromosomes, inherited equally from both parents
mitochondrial DNA: circular chromosome in mitochondria, inherited from mother
chlorplast DNA: circular chromosome, unequally inherited from both parents

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18
Q

what is the general structure and base arrangement of DNA?

A

DeoxyriboNucleic Acid
2 sugar phosphate strands as back bone, connected to the sugar is a nitrogen base pair which are bonded by hydrogen bonds.
(AT CG base pairs)

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19
Q

what is the chromosome count during mitosis and meiosis?

A

mitosis: prophase - metaphase = 46 chromosomes, 92 chromatids
anaphase - telophase = 92 chromosomes, 92 chromatids
cytokinesis = 46 chromosomes, 46 chromosomes, 2 cells

meiosis 1: prophase - telophase = 46 chromosomes, 92
chromatids
cytokinesis = 23 chromosomes, 46 chromatids

meiosis 2: prophase - metaphase = 23 chromosomes, 46
chromatids
anaphase - telophase = 46 chromosomes, 46
chromatids
cytokinesis = 23 chromosomes, 23 chromatids

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20
Q

what is a homologous pair?

A

a pair of maternal and paternal sister chromatids; maternal and paternal chromosomes will replicate and pair up with the corrosponding sister chromatids

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21
Q

how do you predict genotype and phenotype ratios for dominant and recessive, multiple, incompletely dominant, and codominant alleles?

A

Test cross to predict genotype
Dominant alleles mask effect of reccessive alleles
Multiple alleles are a gene with more then 2 alleles, they go in order of dominance a>b>c>d
Incomplete dominance is blending of alleles
Codominance is equal expressing of each allele

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22
Q

how to calculate probability in genetics?

A

P = # of chances for an event/# of possible combinations
If there are 2 events occuring simultaneously (eyes and gender)
multiply; P = (probaility of event 1)(probability of event 2)

23
Q

what are sex-linked traits? sex limited? sex influenced?

A

controlled by genes on sex chromosomes almost always on X chromosome. crossed the same as dominant and recessive.
sex limited - expressed only in one sex, the other can carry the gene but will not express the trait
sex influenced - more common in one sex then another

24
Q

what is gene linkage? how do you do gene mapping?

A

genes that are found on the same chromosome are linked and inherited together. will only seperate during crossing over.

genes on the same chromosome that are further apart are more likely to cross over and seperate (will not be inherited together)
genes on the same chromosome that are closer together are less likely to cross over an seperate (will be inherited together)

*start with the genes that are furthest apart for gene mapping

25
Q

how to predict dihybrid crosses?

A

crossing of 2 traits x 2 traits (the 2 traits are on different chromosomes)
- TtYy –> TY ty tY Ty (do this with other 2 traits and cross them in the punnet square)

26
Q

what is a lethal allele?

A

Lethal alleles are alleles that cause an organism to die only when present in a homozygous condition

27
Q

what are the 2 types of polygenic inheritence?

A

epistatic interaction; Genes that mask the expression of other genes. Ex. the absense of coat color is determined on the inheritance of a homozygous recessive gene

complimentary interation; Occurs when two genotypes combine to create a phenotype that neither can produce alone
Genotype A + Genotype B = Phenotype C

28
Q

what is a pleiotropic gene?

A

A single gene has multiple effects and affect many characteristics throughout the body. Lots of symptoms from one gene
ex. sickle cell amenia

29
Q

what are the 5 modes of inheritance?

A 
Y linked - XY^a or XY^A
autosomal recessive - aa 
autosomal dominant - AA
X linked - X^aX^a or X^aY
X linked dominant - X^AX^A/a X^AY
30
Q

how to determine the mode of inheritance on a pedigree?.

A
  1. check if Y linked only males will be affected.
  2. if not Y linked check if dominant or recessive. dominant will not skip generations, recessive can skip generations.
  3. if dominant check if autosomal or X-linked. if autosomal affected individuals will have atleast one affected parent, if X linked all affected males will have affected mothers and daughters
  4. if recessive check if autosomal or X linked. if autosomal usually will skip generations, if X linked more common in males then females and affected females will have affected dads and sons
31
Q

what is the Hardy Weinberg principle? why is it significant to gene pool stability?

A

The Hardy-Weinberg equilibrium is a principle stating that the genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors. Certain conditions must be met; Large population, Random mating, No genetic drift, No gene flow - migration, No natural selection, No mutations

32
Q

what factors cause the diversity in the gene pool to change?

A 
Small population
Non-random mating
Genetic Drift
Migration (gene flow)
Natural selection
Mutation
33
Q

what are mutations?

A
  • changes in DNA occur during meiosis (chromosomal or point)
  • usually show up in homozygous recessive genotype
  • result in genotypic variations
  • original source of variation, can be good or bad
34
Q

what is genetic drift? what is the founder and bottleneck effect?

A
  • occurs when population size significantly decreases
  • results from chance events (natural disasters, human influence, migration unsuccessful mating)
  • end up with changes in allele frequencies

founder effect –> smaller population forms from a larger population, loss of genetic variation. ex. Amish
bottleneck effect –> few members survive a widespread elimination of a species, decreased genetic variation

35
Q

what is migration?

A

immigration -> members move INTO a population, genes added, gene pool expands
emmigration -> members move OUT a population, genes removed, gene pool contracts

36
Q

what is natural selection?

A

primary mechanism of evolution

Organisms best suited for a given environment will survive and pass their genes on to the next generation

37
Q

what is non random mating?

A
  • selective breeding
  • individuals seek mates within a population
  • particular genes are selected for
  • form of natural selection
38
Q

how to quantitatively use the Hardy-Weinberg principle to observed and published data to determine allele and genotype frequencies?

A

alleles –> p + q =1
genotypes –> p2 + 2pq + q2

p = frequency of dominant allele in a population. (A)
q = frequency of recessive allele in a population. (a)
p2 = frequency of homozygous dominant genotype. (AA)
2pq = frequency of heterozygous genotype. (Aa)
q2 = frequency of homozygous recessive genotype. (aa)
39
Q

describe how a predator/prey relationship must work

A
  • prey are higher in numbers
  • if prey increases, predators increase. if prey decreases, predators decrease
  • if predators > prey then the ecosystem can collapse
40
Q

what is mutualism, commensalism and parasitism?

A

mutualism - both benefit
commensalism - one benefits other is neither benefiting or being harmed
parasitism - one benefits one is harmed

41
Q

what is the difference between intraspecific competition and interspecific competition?

A

intra - same species (human vs human)
intER - diffERent species (lion vs human)

*species can produce fertile offspring

42
Q

what are the 3 types of adaptations?

A

PHYSICAL - structural or anatomical adaptations (ex. mimicry, camaflouge, wings, color)
BEHAVIOURAL - courtship, migration, nocturnalism, estivation(slowing of metabolism based on weather), metabolism, hibernation
PHYSIOLOGICAL - chemical defense, phermones (chemicals secreted), enzymes, venom, toxins.

43
Q

what is the difference between primary and secondary succession?

A

primary begins with bare rock and pioneer species like lichen and then proceeds to seral community (grass, shrubs, small trees) and then finally climax community (most stable, dynamic equilibrium)
ex. glacier receding, volcano eruption

secondary begins with soil and previous vegetation then goes to a climax community. if disturbances occur (forest fire, floods, clear cutting) the climax community will return to secondary succession

44
Q

what are the 4 ways to calculate population change?

A

Population density = total number of organisms/area
change in population = (natality + emigration) - (births + immigration)
growth rate = change in population/time
per capita growth rate = change in population/total number of organisms

45
Q

how to interpret an S shaped curve?

A
  • logistic growth
  • K selected species
  • open system (immigration and emmigration occurs)
46
Q

how to interpret J shaped curve

A
  • exponential growth
  • r selected species
  • closed system (no immigration or emmigration)
  • mortality and natality effect density changes
47
Q

difference between r selected and K selected species?

A

r selected(rats) - unpredictable climate, high mortality, low competition, population size changes randomly, rapid development, early reproductive age, small, high and quick reproductive frequency, short lifespan

K selected(kangaroos) - constant climate, low mortality, constant population size constant over time, high competition, long mature time, large, low reproductive frequency, few offspring in one birth, longer lifespan

48
Q

what are the 2 types of limiting factors? what is environmental resistance?

A

abiotic - flood, fire, droughts. effects population regardless of density (number of individuals)
biotic - parasites, predation starvation
environmental resistance - limiting factors which limit population growth and determine the carrying capacity of a population

49
Q

what is biotic potential? what is a carrying capacity?

A

biotic potential: max reproductive capacity of species
carrying capacity: species average population size in a particular habitat. population size is limited by environmental factors like food, shelter, water, and mates.

50
Q

what are the 3 dispersion patterns?

A

random -> abundant resources, members not likely to compete with each other
clumped -> unevenly distributed, members are likely to be found in close proximity of each other
uniform -> limited resources, members are likely to be territoriality defind to resources

51
Q

what stimulates the release of TSH, thyroxine, calcitonin, PTH?

A

TSH - low metabolic rate
Thyroxine - low metabolic rate
Calcitonin - high blood calcium
PTH - low blood calcium

52
Q

what stimulates release of ACTH, cortisol, aldosterone, epinephrine?

A

ACTH - long term stress
Cortisol - stress, increases level of amino acids which increases level of glucose
Aldosterone - low blood pressure
epinephrine - short term stress (SNS)

53
Q

what stimulates release of inslulin and glucagon?

A

insulin - high glucose level

glucagon - low glucose levels

Biology 30 (2 decks)

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