Core Bio Exam Two

Front 1

When is a gene expressed?

Back 1

when the mature, active protein product is functional in the location where it is supposed to be acting

Front 2

Molecular switches

Back 2

what turns gene expression on and off

Front 3

What can trigger molecular switches?

Back 3

response to environment
during development
tissue specific

Front 4

In multicellular organisms, cell function...

Back 4

is determined by which genes are switched on and off

Front 5

Expression in female mammals

Back 5

in each cell, one X chromosome is inactive due to packing of DNA

Front 6

Histones

Back 6

a protein that DNA coils around

Front 7

Nucleosome

Back 7

group of four histones coiled together

Front 8

Tight helical fiber

Back 8

many nucleosomes coiled together

Front 9

Supercoil

Back 9

large strand made of tight helical fiber coiled together

Front 10

Point of histones/nucleosomes?

Back 10

DNA coiling around these prevents transcription access to these genes

Front 11

Methylation

Back 11

methyl groups on DNA prevent RNA polymerase access to DNA

Front 12

Transcription factor

Back 12

protein that binds to specific DNA sequences to block or promote RNA polymerase

Front 13

Promoter

Back 13

region of DNA that initiates transcription

Front 14

Enhancer

Back 14

short region of DNA that can be bound with proteins to enhance transcription levels

Front 15

TATA box

Back 15

core promoter sequence, binding site of transcription factors or histones

Front 16

TBP

Back 16

TATA-binding protein

Front 17

TAF

Back 17

TBP-associated factors

Front 18

TFIID

Back 18

part of the transcription initiation complex

Front 19

Other proteins involved in regulation?

Back 19

co-activators
suppressors
regulators

Front 20

Expression of transcription factors?

Back 20

feedback loops (presence/absence of product a protein works on)
signals from other cells (hormones, etc)

Front 21

Signal transduction

Back 21

mechanism that converts mech/chem cell stimulus into specific cellular response

Front 22

Relay proteins

Back 22

proteins that relay the signal transduction message to the transcription factors

Front 23

Protein phosphorylation

Back 23

addition of a phosphate to a protein
turns many proteins on and off

Front 24

Transcription factors...

Back 24

activate more than one gene in the same process

Front 25

Introns

Back 25

sections of RNA that interrupt sequences

Front 26

Exons

Back 26

sections of RNA that are expressed

Front 27

Alternative splicing

Back 27

removal of different introns that expresses to create different proteins

Front 28

spliceosomes

Back 28

RNA and protein units that remove introns from pre-mRNA sequence

Front 29

Later stages of gene expression regulation

Back 29

lifetime of mRNA molecule helps determine how much protein is made
protein may need to be activated

Front 30

Post-transcription regulation of mRNA/protein

Back 30

bound to another protein
broken down by enzymes (fast or slow)
protein - may/may not be properly folded
protein - may/may not be in proper place in cell

Front 31

Regulation places in a nutshell:

Back 31

access to DNA
transcription factors/RNA
alternative splicing
access to/persistence of mRNA
access to/persistence of protein

Front 32

Mutation

Back 32

a permanent change in the sequence of DNA
the ultimate source of all genetic variation

Front 33

Somatic tissue

Back 33

regular body tissue

Front 34

Germinal tissue

Back 34

tissue of the sex cells

Front 35

Causes of mutation:

Back 35

Radiation (extra energy changes stability)
Chemical
Chance (constant regeneration increases probability)

Front 36

Point mutation

Back 36

single to few nucleotide change

Front 37

Other types of mutation:

Back 37

deletions
insertions
frame-shift

Front 38

Silent

Back 38

Point mutation, no change in amino acid

Front 39

Non-sense

Back 39

Point mutation, change to a STOP codon

Front 40

Mis-sense

Back 40

Point mutation, different amino acid

Front 41

Do changes become fixed into mutations?

Back 41

Yes, after being copied in DNA transcription.

Front 42

Methylation

Back 42

Old DNA strand methylated, new strand isn't
dcm & dam - A&C methylator enzymes that mark bacterial DNA

Front 43

Proofreading

Back 43

there may be a bump that the proofreaders catch
when fixing, use methylated side as original

Front 44

Hemi-methylated

Back 44

one strand methylated, other strand not

Front 45

Reading frame

Back 45

codon

Front 46

Leaky mutant

Back 46

when expressed protein isn't completely finished

Front 47

Hemoglobin

Back 47

oxygen carrying molecule
280 million per red blood cell

Front 48

DNA error repair

Back 48

error in 1 for every 105 bases
proofreading
mismatch repair
excision repair

Front 49

SNPs

Back 49

single nucleotide polymorphisms
may or may not cause a restriction pattern site in genes

Front 50

Difference between people?

Back 50

0.1% DNA difference (1 in 1,000 bases)
~3 million differences

Front 51

genotype

Back 51

gene sequence

Front 52

phenotype

Back 52

expression of gene sequence

Front 53

gene

Back 53

group of codons that have an expression

Front 54

allelle

Back 54

variation of a gene

Front 55

homozygus

Back 55

same allelle (A & A)

Front 56

heterozygus

Back 56

different allelles (A & B)

Front 57

gene pool

Back 57

different allelles of same gene

Front 58

pleitropy

Back 58

1 gene can have multiple phenotypic effects

Front 59

epistasis

Back 59

all other effects on expression aside from genomic (inheritable)

Front 60

restriction enzymes

Back 60

cut DNA on specific palendromic sequences

Front 61

restriction fragment length polymorphisms

Back 61

cut at different sites depending on genetic variation, so resulting fragments are of different lengths

Front 62

restriction map

Back 62

"map" of the DNA banding pattern from gel electropherograms

Front 63

haplotype

Back 63

specific combinations of SNPs within a short region of DNA, not necessarily same gene

Front 64

Polymerase chain reaction

Back 64

DNA + nucleotides + buffer & DNA polymerase + primer

Front 65

PCR thermocycling?

Back 65

denaturation
annealing
extension
doubles DNA after 1 cycle

Front 66

Genome

Back 66

totality of an organism's genetic material
each cell contains the entire genome

Front 67

Genomic DNA is organized in..

Back 67

chromosomes

Front 68

Chromosomes

Back 68

present in pairs b/c sexual reproduction

Front 69

Chromatid

Back 69

one half of an x shaped chromosome

Front 70

Centromere

Back 70

place where chromatids meed

Front 71

Humans have...

Back 71

23 pairs of linear chromosomes

Front 72

Binary fission

Back 72

bacterial reproduction
BF2 - chromosome is replicated
BF3 - cell grows, chromosomes separate
BF4 - more growth, separation
BF5 - chromosomes totally separate
BF6 - Cell membrane/wall pinch in
BF7 - Division complete

Front 73

Mitosis

Back 73

eukaryote cell cycle & cell division

Front 74

Chromosomes in diploid organisms?

Back 74

come in pairs, numbered by size

Front 75

Cell cycle

Back 75

gap 1
DNA synthesis
gap 2
mitosis
(from G1 to G2 is interphase)

Front 76

S phase

Back 76

after s phase, chromosomes ahve two chromatids, daughter molecules. held together by centromere.

Front 77

Phases of mitosis:

Back 77

prophase
metaphase
anaphase
telophase

Front 78

Prophase

Back 78

DNA condenses
nucleus breaks down
chromosomes attach to spindle fibers

Front 79

Metaphase

Back 79

chromosomes move to center of cell (equatorial plate)

Front 80

Anaphase

Back 80

centromeres split
chromosomes move to opposite cell sides

Front 81

Telophase

Back 81

nuclei reform
chromosomes uncondense
cells pinch off - cytokinesis

Front 82

Meiosis

Back 82

2 consecutive divisions
reduction division
makes haploid gamete cells

Front 83

Phases of Meiosis

Back 83

prophase 2
metaphase 2
anaphase 2
telophase 2

Front 84

Distribution of chromosomes...

Back 84

each gamete gets one of the homologous chromosomes of each pair

Front 85

Prophase - meiosis

Back 85

csomes condense
n.membrane breaks down
homologs pair up

Front 86

Metaphase - meiosis

Back 86

paired chromosomes move to center of cell

Front 87

Anaphase - meiosis

Back 87

homologs pulled apart
(they stay 2 chromatid chromosomes)

Front 88

Prophase 2 - meiosis

Back 88

csomes condense
nuclear membrane breaks down
spindle forms & csomes attach

Front 89

Metaphase 2 - meiosis

Back 89

csomes move to center of cell

Front 90

Anaphase 2 - meiosis

Back 90

csomes split at centromere
chromatids separate, move to opposite sides
(resulting cells = haploid)

Front 91

Function of meiosis

Back 91

creates haploid gametes
to recombine genes for variable offspring through random sorting & crossing over

Front 92

Sperm formation

Back 92

equal division of cell mass each time

Front 93

Egg formation

Back 93

one cell stays very large through meiosis (egg) , other 3 called polar bodies

Front 94

Fertilization

Back 94

1n sperm + 1n egg = 2n zygote

Front 95

karyotype

Back 95

chromosomes laid out diagram like

Front 96

Movement of cancer cells

Back 96

lose contact inhibition & attachment - can now move anywhere & form tumor

Front 97

Causes of indefinite replication?

Back 97

mutation of telomerase
mutation of growth hormone receptors
tumor receptor gene deregulated
virus infection