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voice of the genome Flashcards

1
Q

formula to work out how many possible combos of chromosomes in gametes

A

2^n
n is no of pairs of homologous chromosomes

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2
Q

what does meiosis produce

A

gametes
4 genetically different haploid cells

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3
Q

what is crossing over

A

homologous chromosomes pair up to form bivalents
non sister chromatids can cross over and get entangled at chiasmata
results in new combo of alleles

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4
Q

what is independent assortment

A

homologous chromosomes arranged randomly on equator
pulled to opposite poles
diff allele combos produced

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5
Q

what is a diploid cell

A

has 2 copies of each chromosome

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6
Q

what is a haploid cell

A

has 1 copy of each chromosome

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7
Q

what is the effect of calcium ions on a sperm cell

A

cause the acrosome reaction to occur before the sperm cell reaches the egg

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8
Q

what is the acrosome reaction?

A

digestive enzymes from acrosome digest zone pellucida so sperm can enter egg cell

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9
Q

what is the cortical reaction

A

cortical granules in the egg cell release chemicals that cause the zone pellucida to harden
preventing more sperm from entering

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10
Q

what is formed when sperm and egg nuclei fuse

A

dipole zygote

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11
Q

what does the sperm cell mid piece contain lots of and why

A

mito
provide energy for flagella movement so can swim to egg

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12
Q

is an egg or sperm cell larger

A

egg

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13
Q

what is the function of follicle cells in an egg cell

A

protective coating

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14
Q

what is a gene

A

section of DNA that codes for a polypeptide/ protein

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15
Q

what is a locus

A

position of a gene on a chromosome

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16
Q

what is an autosome

A

a chromosome that is not a sec chromosome

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17
Q

what is autosomal linkage

A

2 or more genes on same autosome do not assort independently during meiosis
linked and stay together
passed onto offspring together

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18
Q

what are the female sex chromosomes

A

XX

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19
Q

what are the male sex chromosomes

A

XY

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20
Q

what is a stem cell

A

undifferentiated cell that can divide by mitosis an unlimited amount of times

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21
Q

what can totipotent stem cells differentiate into

A

embryonic
extra embryonic (placenta, umbilical cord)

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22
Q

what can pluripotent stem cells differentiate into

A

embryonic

23
Q

what can multi potent stem cells differentiate into

A

adult stem cells

24
Q

what is the process of cell differentiation

A

under certain conditions, some genes in a stem cell are activated

mRNA only transcribes from activated genes

mRNA translated to form proteins

protein structure responsible for modifying cell

25
Q

what are transcription factors

A

protein that controls expression and therefore transcription of genes by binding to a specific region of DNA

26
Q

what are activators

A

transcription factors that increase the rate of transcription
help RNA polymerase bind to DNA at start of gene

27
Q

what are repressors

A

transcription factors that decrease the rate of transcription
stop RNA polymerase binding to DNA at start of gene

28
Q

what is the promotor region

A

DNA sequence that RNA polymerase initially binds to

29
Q

how is gene expression controlled in prokaryotes

A

transcription factors binding to operons

30
Q

what is an operon

A

a section of DNA that includes:

cluster of structural genes transcribed together

promotor region

operator region (where transcription factors bind)

maybe regulatory genes that code for activators or repressors

31
Q

what is the function of lactase

A

breaks down lactose so it can be used as an energy source in bacterial cells

32
Q

what does the lac operon control

A

production of enzyme lactase

33
Q

what happens when lactose is absent in prokaryotes

A

regulatory gene transcribed and translated

lac repressor protein produced

binds to operator region

RNA polymerase cant bind to promotor region

no transcription of structural genes

no lactase enzyme synthesised

34
Q

what happens when lactose is present in prokaryotes

A

bac uptakes lactose

lactose binds to 2nd binding site on repressor protein

repressor protein shape distorts, cannot bind to operator region

RNA polymerase binds to promotor region

transcription

mRNA from all 3 structural genes translated

lactase produced

lactose broken down, used for energy

35
Q

what is the role of the RER

A

process proteins made on ribosomes

36
Q

what is the structure of the RER

A

formed from folds of membrane continuous with the nuclear envelope

surface covered in ribosomes

37
Q

what is the function of the SER

A

production, processing and storage of lipids, carbohydrates and steroids

38
Q

does the SER have ribosomes on its surface

A

no

39
Q

what is the role of the Golgi body

A

modify proteins and lipids before packaging them into Golgi vesicles

40
Q

what is the Golgi body made of

A

flattened sacs of membrane

41
Q

how can the Golgi body be distinguished from the SER

A

by its regular, stacked appearance

it can be described as looking like a wifi symbol

42
Q

what is the function of lysosomes

A

contain hydrolytic enzymes
break down waste materials

43
Q

do new proteins go to the RER or Golgi first

A

RER

44
Q

is DNA positively or negatively charged

A

negatively

45
Q

do epigenetic occur in prokaryotes or only eukaryotes

A

only eukaryotes

46
Q

what could cause epigenetic changes

A

stress
diet
exercise
toxins- smoking

47
Q

what is methylation

A

methyl groups bind to DNA

methyl is positively charged and DNA is neg so they attract and DNA is tightly coiled to form heterochromatin

transcription factors cant bind to DNA

increased methylation inhibits transcription

48
Q

what is acetylation

A

acyl groups bind to histone proteins

acyl groups are negatively charged like DNA so they repel and DNA isn’t tightly coiled

transcription factors can bind to DNA

decreased acetylation inhibits transcription

49
Q

are epigenetic changes heritable

A

yes

50
Q

for drug testing, what do modern preclinical trials test on

A

human tissues
animals

51
Q

for drug testing, what occurs in phase 1 of clinical trials

A

small group of healthy individuals
monitor side effects
find correct safe dosage

52
Q

for drug testing, what occurs in phase 2 of clinical trials

A

tested on patients
for effectiveness
placebos
in a double blind trial

53
Q

for drug testing, what occurs in phase 3 of clinical trials

A

compare to existing drugs
patients in 2 groups
double blind trial

bio (8 decks)

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