Genetics And Cellular And Molecular Biology

Front 1

What is RNA and DNA made of?

Back 1

phosphate group, 5 carbon sugar and nitrogenous base

Front 2

what are the types of nitrogenous base and their pairs?

Back 2

pyrimidines: thymine and cytosine

purine: adenine and guanine

thymine pairs with adenine

guanine pairs with cytosine

Front 3

what is the shape of DNA

Back 3

anti- parallel, and a double stranded helix

Front 4

what are the 3 levels of condensation of DNA

Back 4

1: packaging DNA into nucleosomes

2: supercoiling

3: attachment of fibres to a protein scaffold

Front 5

explain the first level of condensation

Back 5

-starts as 2nm and goes to 11nm

-146 nucleotide pairs wrap around an octamer of histones

-wrapped around 8 histone proteins and anchored by 9th histone (H1)

Front 6

whats a complete nulceosome in condenstation?

Back 6

8 histones, 146 base pairs and histone H1

Front 7

what can happen to linker DNA?

Back 7

linker DNA can be susceptible to digestion by endonuclease

Front 8

what happens in the second level of condensation?

Back 8

-condenses to 11nm to 30nm

-the nucleosomes wrap around each other

Front 9

what happens in the third level of condensation?

Back 9

30nm fibre is attached at many positions to a protein scaffold

Front 10

what are the two proteins used in the third level of condensation and what do they do?

Back 10

cohesin: proteins that hold the two arms together

codensin: condenses the 30nm of chromatin within one sister chromosome

Front 11

what are the three parts of the chromosomes?

Back 11

p arm: refers to the short arm

q arm: refers to the long arm

centromere: point of attachment of chromosomes microtubules in miotic spindle

Front 12

what do telomeres do?

Back 12

protect the end of the chromosomes, prevent fusion and facilitate replications

Front 13

where does mitosis occur?

Back 13

in all non-germ cells

Front 14

what are the 5 phases of the cell cycle and what happens?

Back 14

G1: growth, cellular metabolism

S: DNA replication

G2: prep for mitosis

M: mitosis

interphase: time between successive mitosises

Front 15

what is a sister chromatid?

Back 15

make up a chromosome and are identical

Front 16

haploid vs diploid vs DNA content (in terms of n and c)

Back 16

haploid: 'n' and 'c' amounts of DNA, one chromosome

diploid: 2'n' and 2'c', one unique chromosome from mom and dad

Front 17

what are the 6 steps in mitosis

Back 17

interphase, prophase, metaphase, anaphase, telophase and cytokinesis

Front 18

interphase:

Back 18

-chromosomes duplicate to produce sister chromatid

-sister chromatid are homologs

Front 19

prophase:

Back 19

-duplicated chromosomes condense

-nulceolus disappears

-nuclear membrane starts to breakdown

Front 20

metaphase:

Back 20

chromosomes migrate to the middle

Front 21

anaphase:

Back 21

sister chromatids pull apart and move to opposite poles of the cell

-cohesin breaks down

Front 22

telophase:

Back 22

chromsomes decondense and new nuclear membrane forms

-new daughter cells are 2c and 2n

Front 23

cytokinesis

Back 23

membrane forms between daughter cells

Front 24

where does meiosis occur and what does it produce?

Back 24

-occurs in germ cells

-results in 4 haploid genetically distinct cells

Front 25

what are the steps in meiosis?

Back 25

meiosis I: prophase 1, metaphase 1, anaphase 1, telopahse 1

meiosis 2: prophase 2, metaphase 2, anaphase 2, telophase 2

Front 26

what are the steps in prophase 1:

Back 26

-leptonema: sister chromatids condense

-zygonema: homologous coromosomes begin to pair

-pachynema: crossing over occurs here

-diplonema: homologous chromosomes seperate at the chiasmata

Front 27

explain crossing over

Back 27

breakage of chromatids and the exchage of broken pieces between homologous chromosomes

Front 28

what happens in metaphase 1 and 2?

Back 28

-1: paired chromosomes align in the middle

-2: chromosomes align in the middle

Front 29

what happens in anaphase 1 and 2?

Back 29

-1: homologous chromosomes disjoin andmove to opposite poles

-2: sister chromatids disjoin and go to opposite poles

Front 30

what happens in telophase 1 and 2?

Back 30

-1: new nuclei begin to form (n;2c)

-2: haploid cells are seperated by cytoplasmic membranes (n;c)

Front 31

whats the difference between a locus and an allele?

Back 31

locus: fixed position on a chromosome

allele: alternate form of a gene (Aa)

Front 32

what is a genotype?

Back 32

a genotype refers to the allelic combination

Front 33

what is a phenotype?

Back 33

the physical appearance caused by the allelic combination

Front 34

what is the difference between homozygous and and heterozygous?

Back 34

homozygous: both alleles and identical; either dominant or recessive

heterozygous: two alleles are different

Front 35

what are the three designations when doing crosses?

Back 35

P: parent generation

F1: parents offspring

F2: parents grand-offspring

Front 36

what is the genotypic and phenotypic ratio for a monohybrid cross?

Back 36

1,2:1 and 3:1

Front 37

what is Mendel's principle of inheritance?

Back 37

in heterozygous, dominant allele masks the recessive

Front 38

Mendel's principle of segregation?

Back 38

in a heterozygous, two alleles segregate from each other during formation of gametes

Front 39

Mendel's principle of independent assortment?

Back 39

alleles on different pairs of chromosomes assort independently from one another

Front 40

pseudoautosomal:

Back 40

found in the terminal region, genes that don't follow the X or Y linked pattern

Front 41

What's the difference between heterozygous and hemizygous?

Back 41

heterozygous: recessive allele is masked by dominant allele (XX)

hemizygous: recessive allele would manifest because there is nothing to mask it (XY)

Front 42

what happens to the second X chromosomes in women?

Back 42

X- chromosome condenses into darkly staining matter called Barr Body

Front 43

what is a spontaneous mutations?

Back 43

error during DNA synthesis when are isoforms of the bases occur

Front 44

what are the alternate forms of the bases?

Back 44

keto-thymine: enol form

amino-cytosine: imino form

amino-adenine: imino form

keto- guanine: enol form

Front 45

what happens in the isoforms of the bases?

Back 45

adenine and cytosine bound and guanine and thymine bound

Front 46

what are the hot spots for spontaneous mutations?

Back 46

simple repeats, symmetrical repeats and palindromes

Front 47

what are the two types of chemical mutagens?

Back 47

-mutagenic only to replicating DNA(base analogues, acridine dye)

-mutagenic to both replicating and non-replicating DNA

Front 48

what can cause chemical mutations?

Back 48

UV rays can cause thymines to mutate into thymine dimers

Front 49

what are transposable elements?

Back 49

virus puts segments into DNA which causes early stoppage

Front 50

what are the type of single base (point) mutations?

Back 50

silent: no effect to resulting amino acid

nonsense: results in early stop

missense: changes one amino acid

Front 51

what are the types of frameshift mutations?

Back 51

insertion: insertion of base pair, shifts coding to the right

deletion: deletion of base pair, shifts coding to the left

Front 52

expanding genes

Back 52

expanding genes show increased severity and severity earlier in life by generation

Front 53

mutations that affect coding regions

Back 53

changes the protein to a non-functional form

-premature truncation

-changes protein folding

-changes post- translational modification

Front 54

mutations that affect non-coding regions

Back 54

prevent or reduce transcription or translation

Front 55

what is incomplete dominance?

Back 55

one allele is partially or incompletely dominant over the other

Front 56

what is codominance?

Back 56

heterozygotes express both phenotypes of both the homozygotes

-blood type (AB)

Front 57

what is the allelic series?

Back 57

a hierarchy displayed by the dominance of mutations within themselves

Front 58

what is a test cross?

Back 58

if you want to find the genotype of something, cross is with a homozygous being

Front 59

complementation test?

Back 59

cross two mutations together to see if a new mutation forms

Front 60

what are the 3 stages in transcription?

Back 60

initiation, elongation and post-translational modifications

Front 61

what happens in initiation (transcription)?

Back 61

RNA polymerase binds ta the DNA upstream of gene being copied (promoter)

-rich in A's and T's

Front 62

what happens in elongation (transcription)?

Back 62

-once bound to the promoter, the polymerase builds the mRNA single strand in 5prime to 3prime

-only one DNA is copied, called the template strand

-as polymerase passes, double helix reforms

Front 63

what happens during post- translational modifications?

Back 63

-capping and tailing: 50- 250 adenines added to the 3prime, 5prime cap of 7 guanine to initiate translation

-introns removed: introns are removed by spliceosomes as they don't code for amino acids

Front 64

what are the 3 stages of translation?

Back 64

initiation, elongation and termination

Front 65

what happens in initiation (translation)?

Back 65

-large and small ribosome subunits associate with mRNA

-tRNA molecule containing amino acid Met joins to small ribosomal unit at the P site

-complex binds to the 5prime cap of mRNA and large ribosomal subunit binds to complete ribosome

Front 66

what happens in elongation (translation)?

Back 66

-tRNA is bound at the P site

-next tRNA w/ anticodon and amino acid bind to A site

-met is cleared and forms polypeptide bind with amino acid on A site tRNA

-ribosomes move along the mRNA to the next codon and empty tRNA moves to E site and is released

-tRNA move from A site to P site and new tRNA brings amino acid to A site

Front 67

what happens in termination (translation)?

Back 67

-A site arrives at stop codon

-polypeptide is released