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Biology > Inherited Change > Flashcards

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
Q

definition of recessive

A

phenotype of allele only expressed when dominant allele is not present

26
Q

definition of codominant

A

more than or two phenotypes possible;

phenotype of heterozygote different from homozygous;

27
Q

definition of F1 generation

A

offspring resulting from cross between homo-dom + homo-recc

28
Q

definition of F2 generation

A

offspring resulting from cross between two F1 organisms

29
Q

definition of autosomal linkage

A

when one or two more genes on same chromosome tends to be inherited together and are on autosomes

30
Q

describe how sickle cell anemia is caused

A

mutation of base substitution from

glutamic acid to valine

31
Q

describe the link between sickle cell anemia and malaria (5)

A 
sickle cell cannot carry O2 well;
homozygous HS die;
heterozygous has trait + less likely to suffer from malaria;
malaria is lethal;
selective advantage;
32
Q

example of sex linked gene

A

haemophilia - blood fails to clot

33
Q

gene used for blood clotting

A

factor VIII

34
Q

why are males more likely to have haemophilia

A

females have XX so it needs both chromosomes

35
Q

ratio of dihybrid crosses with (het/homo) + (het/het)

A

1: 1:1:1 = heterozygous crossed with homozygous recessive
9: 3:3:1 = heterozygous crossed with heterozygous

36
Q

how can you tell the test cross is autosomal linkage

A

NOT 9:3:3:1/1:1:1:1 ratio;
large number of parental phenotype;
no independant assortment;

37
Q

what does COV value show

A

probability of genes being independanly assorted = high value - large distance = more likely to split

38
Q

describe mutation

A

random change in base sequence of DNA

39
Q

examples of mutations

A

albinism (homo rec)

huntington’s (dom)

40
Q

describe the cause of albinism

A

dark pigment melanin missing

no tyrosinase

41
Q

describe the cause of huntington’s disease

A

neurological disorder = mental+ physical deterioation

repeated triplet bases of CAG

42
Q

definition of structural genes

A

structural protein;
enzyme/tRNA;
needed for structure in cell;

43
Q

definition of regulatory genes (5)

A 
control gene expression;
codes for transcription factor;
binds to promoter;
stops/allows binding of RNA polymerase;
examples: lac repressor;
44
Q

definition of constitutive genes

A

makes protein all the time

45
Q

definition of facultive genes

A

only transcribed when needed

46
Q

definition of repressible enzymes

A

synthesis of repressible enzymes inhibited by binding repressor protein on specific site

47
Q

definition of inducible enzymes

A

synthesis only occurs when substrate is present

48
Q

describe the diagram of lac operon

A

reg gene - promoter - operator - Z - Y - A

49
Q

what is lacZ

A

B galactosidase (lactose into glucose and galactose)

50
Q

what is lacY

A

permease (increase permeability for lactose)

51
Q

what is lacA

A

transcetylcase (transfer acetyl group from CoA to galactose)

52
Q

describe gene control when no lactose is present

A

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
Q

how do we remember the lac operon

A

I Poop On Zebras You Ass

54
Q

describe gene control when lactose is present

A

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
Q

why do we need to switch on/off production of enzymes

A

proteins in excess;
waste of amino acids;
decrease growth

56
Q

describe gene control in eukaroytes

A

transcription factors bind to promoter region;
TF binds to DNA;
binds to RNA polymerase;
allows transcription;

57
Q

what do transcription factors determine

A

sex in mammals;
responses to environmental stimuli;
allowing hormones to take effect;

58
Q

where does the repressor bind on (DNA)

A

operator

59
Q

where does the RNA polymerase bind to

A

promoter

60
Q

describe the plant hormone gibberilin controlling seed germination (6)

A

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
Q

definition of locus

A

position of gene on chromosome

Biology (19 decks)

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