voice of the genome

Question 1

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

Answer 1

2^n
n is no of pairs of homologous chromosomes

Question 2

what does meiosis produce

Answer 2

gametes
4 genetically different haploid cells

Question 3

what is crossing over

Answer 3

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

Question 4

what is independent assortment

Answer 4

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

Question 5

what is a diploid cell

Answer 5

has 2 copies of each chromosome

Question 6

what is a haploid cell

Answer 6

has 1 copy of each chromosome

Question 7

what is the effect of calcium ions on a sperm cell

Answer 7

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

Question 8

what is the acrosome reaction?

Answer 8

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

Question 9

what is the cortical reaction

Answer 9

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

Question 10

what is formed when sperm and egg nuclei fuse

Answer 10

dipole zygote

Question 11

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

Answer 11

mito
provide energy for flagella movement so can swim to egg

Question 12

is an egg or sperm cell larger

Answer 12

egg

Question 13

what is the function of follicle cells in an egg cell

Answer 13

protective coating

Question 14

what is a gene

Answer 14

section of DNA that codes for a polypeptide/ protein

Question 15

what is a locus

Answer 15

position of a gene on a chromosome

Question 16

what is an autosome

Answer 16

a chromosome that is not a sec chromosome

Question 17

what is autosomal linkage

Answer 17

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

Question 18

what are the female sex chromosomes

Answer 18

XX

Question 19

what are the male sex chromosomes

Answer 19

XY

Question 20

what is a stem cell

Answer 20

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

Question 21

what can totipotent stem cells differentiate into

Answer 21

embryonic
extra embryonic (placenta, umbilical cord)

Question 22

what can pluripotent stem cells differentiate into

Answer 22

embryonic

Question 23

what can multi potent stem cells differentiate into

Answer 23

adult stem cells

Question 24

what is the process of cell differentiation

Answer 24

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

Question 25

what are transcription factors

Answer 25

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

Question 26

what are activators

Answer 26

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

Question 27

what are repressors

Answer 27

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

Question 28

what is the promotor region

Answer 28

DNA sequence that RNA polymerase initially binds to

Question 29

how is gene expression controlled in prokaryotes

Answer 29

transcription factors binding to operons

Question 30

what is an operon

Answer 30

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

Question 31

what is the function of lactase

Answer 31

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

Question 32

what does the lac operon control

Answer 32

production of enzyme lactase

Question 33

what happens when lactose is absent in prokaryotes

Answer 33

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

Question 34

what happens when lactose is present in prokaryotes

Answer 34

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

Question 35

what is the role of the RER

Answer 35

process proteins made on ribosomes

Question 36

what is the structure of the RER

Answer 36

formed from folds of membrane continuous with the nuclear envelope surface covered in ribosomes

Question 37

what is the function of the SER

Answer 37

production, processing and storage of lipids, carbohydrates and steroids

Question 38

does the SER have ribosomes on its surface

Answer 38

no

Question 39

what is the role of the Golgi body

Answer 39

modify proteins and lipids before packaging them into Golgi vesicles

Question 40

what is the Golgi body made of

Answer 40

flattened sacs of membrane

Question 41

how can the Golgi body be distinguished from the SER

Answer 41

by its regular, stacked appearance it can be described as looking like a wifi symbol

Question 42

what is the function of lysosomes

Answer 42

contain hydrolytic enzymes break down waste materials

Question 43

do new proteins go to the RER or Golgi first

Answer 43

RER

Question 44

is DNA positively or negatively charged

Answer 44

negatively

Question 45

do epigenetic occur in prokaryotes or only eukaryotes

Answer 45

only eukaryotes

Question 46

what could cause epigenetic changes

Answer 46

stress diet exercise toxins- smoking

Question 47

what is methylation

Answer 47

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

Question 48

what is acetylation

Answer 48

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

Question 49

are epigenetic changes heritable

Answer 49

yes

Question 50

for drug testing, what do modern preclinical trials test on

Answer 50

human tissues animals

Question 51

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

Answer 51

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

Question 52

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

Answer 52

tested on patients for effectiveness placebos in a double blind trial

Question 53

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

Answer 53

compare to existing drugs patients in 2 groups double blind trial