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Inherited Change Flashcards

1
Q

describe the composition of chromosomes in human body

A

22 homologous chromosomes/autosomes

one sex chromosome (XX= female/XY= male)

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2
Q

definition of inheritance

A

transmission of genetic information from generation to generation

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3
Q

definition of chromosome

A

thread like structure of DNA containing genes

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4
Q

definition of haploid cell

A

one complete set of chromosomes (n=23 chromosome)

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5
Q

definition of diploid cell

A

two complete sets of chromosomes (2n = 46)

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6
Q

definition of meiosis

A

reduction division resulting in four daughter haploid cells

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7
Q

describe independant assortment

A

different chromosomes combination and chromosomes line up randomly by equator

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8
Q

describe meiosis I

A 
prophase:
chromosomes become visible
condensation
nuclear envelope disappears
centrioles migrate to opposite poles;
spindle forms;
bivalents form;
chiastmata formation;
metaphase:
bivalent line across the equator
spindle attach to centromere
anaphase:
whole chromosomes pulled by microtubules to opposite poles
telophase:
nuclear envelope reforming
nucleolus reforming
cytokinesis
two cell containing 23 chromosomes
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9
Q

when do centrioles replicate and move to poles + chromosomes condense

A

early prophase

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10
Q

when do homologous chromosomes pair up to form bivalents

A

middle prophase

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11
Q

describe meiosis II

A

same process as normal meiosis (no bivalent forming bcos already there)
BUT
anaphase = centromeres divide and pull chromatids to opposite poles
form four haploid cells

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12
Q

describe spermatogenesis

A

diploid cells divide by mitosis
spermatogonia - primary spermatocytes - + meiosis I - secondary spermatocytes (haploid) - + meiosis II - spermatids - spermatozoa

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13
Q

describe oogensis

A

diploid cells divide by mitosis
oogonia - (stop prophase I) - primary oocytes - continue to end of meiosis I - two haploid cells - secondary oocyte/one polar body - secondary oocyte released per month

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14
Q

how is a zygote formed

A

ovum + spermatozoan

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15
Q

which are the male parts in plants

A

anther

filament

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16
Q

which are the female parts in plants

A

stigma
style
ovary

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17
Q

describe formation of male gametes

A

pollen mother cells divide by meiosis to form 4 haploid cells;
each divide by mitosis to form 4 haploid cells with two nucleus;
mature into pollen grains;
generative + tube nucleus

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18
Q

describe formation of female gamete

A

spore mother cell divide by meiosis to form 4 haploid cells
three degenerates - one haploid devleops into embryo sac
sac grows - haploid nucleus divide by mitosis 3 times to form 8 - one nuclei becomes female gamete

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19
Q

definition of fertilisation in plant

A

pollen grain male gamete fuses with female gamete in ovule

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20
Q

definition of genotype

A

alleles possessed by an organism

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21
Q

definition of homozygous

A

having two identical alleles of a gene

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22
Q

definition of heterozygous

A

having two different alleles of a gene

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23
Q

definition of phenotype

A

observable characteristics resulting from genotype and environment

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24
Q

definition of dominant

A

phenotype of allele is expressed both in hetero/homo zygous

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25
definition of recessive
phenotype of allele only expressed when dominant allele is not present
26
definition of codominant
more than or two phenotypes possible; | phenotype of heterozygote different from homozygous;
27
definition of F1 generation
offspring resulting from cross between homo-dom + homo-recc
28
definition of F2 generation
offspring resulting from cross between two F1 organisms
29
definition of autosomal linkage
when one or two more genes on same chromosome tends to be inherited together and are on autosomes
30
describe how sickle cell anemia is caused
mutation of base substitution from | glutamic acid to valine
31
describe the link between sickle cell anemia and malaria (5)
``` sickle cell cannot carry O2 well; homozygous HS die; heterozygous has trait + less likely to suffer from malaria; malaria is lethal; selective advantage; ```
32
example of sex linked gene
haemophilia - blood fails to clot
33
gene used for blood clotting
factor VIII
34
why are males more likely to have haemophilia
females have XX so it needs both chromosomes
35
ratio of dihybrid crosses with (het/homo) + (het/het)
1: 1:1:1 = heterozygous crossed with homozygous recessive 9: 3:3:1 = heterozygous crossed with heterozygous
36
how can you tell the test cross is autosomal linkage
NOT 9:3:3:1/1:1:1:1 ratio; large number of parental phenotype; no independant assortment;
37
what does COV value show
probability of genes being independanly assorted = high value - large distance = more likely to split
38
describe mutation
random change in base sequence of DNA
39
examples of mutations
albinism (homo rec) | huntington's (dom)
40
describe the cause of albinism
dark pigment melanin missing | no tyrosinase
41
describe the cause of huntington's disease
neurological disorder = mental+ physical deterioation | repeated triplet bases of CAG
42
definition of structural genes
structural protein; enzyme/tRNA; needed for structure in cell;
43
definition of regulatory genes (5)
``` control gene expression; codes for transcription factor; binds to promoter; stops/allows binding of RNA polymerase; examples: lac repressor; ```
44
definition of constitutive genes
makes protein all the time
45
definition of facultive genes
only transcribed when needed
46
definition of repressible enzymes
synthesis of repressible enzymes inhibited by binding repressor protein on specific site
47
definition of inducible enzymes
synthesis only occurs when substrate is present
48
describe the diagram of lac operon
reg gene - promoter - operator - Z - Y - A
49
what is lacZ
B galactosidase (lactose into glucose and galactose)
50
what is lacY
permease (increase permeability for lactose)
51
what is lacA
transcetylcase (transfer acetyl group from CoA to galactose)
52
describe gene control when no lactose is present
NO TRANSCRIPTION Regulatory gene codes for repressor protein Repressor binds to operator (part of DNA) RNA polymerase cannot move and bind to promoter No transcription of three structural genes
53
how do we remember the lac operon
I Poop On Zebras You Ass
54
describe gene control when lactose is present
TRANSCRIPTION Lactose taken up by bacterium Lactose binds to repressor protein Repressor protein is allosteric Shape is distorted and prevents binding to DNA RNA polymerase can pass and transcribe three structural genes
55
why do we need to switch on/off production of enzymes
proteins in excess; waste of amino acids; decrease growth
56
describe gene control in eukaroytes
transcription factors bind to promoter region; TF binds to DNA; binds to RNA polymerase; allows transcription;
57
what do transcription factors determine
sex in mammals; responses to environmental stimuli; allowing hormones to take effect;
58
where does the repressor bind on (DNA)
operator
59
where does the RNA polymerase bind to
promoter
60
describe the plant hormone gibberilin controlling seed germination (6)
DELLA protein bound to PIF (transcription factor) PIF cannot bond to gene promoter Gibberillin bonds with receptor and enzyme Initiates destruction of DELLA protein PIF binds to promoter and transcription is initiated Stimulating synthesis of amylase by mRNA coding for amylase
61
definition of locus
position of gene on chromosome

Biology (19 decks)

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