Biology 197 Mitosis Meiosis

Front 1

Genome

Back 1

All the DNA in a cell

Front 2

Telomeres

Back 2

Chromosome ends

Front 3

Somatic cells

Back 3

non reproductive cells that have 2 sets of chromosomes

Front 4

Gametes

Back 4

reproductive cells (sperm and egg) have half as many chromosomes as somatic cells

Front 5

Mitosis

Back 5

The division of the nucleus

Front 6

Cytokinesis

Back 6

The division of the cytoplasm

Front 7

Prophase

Back 7

Replicated chromosomes thicken and shorten. Centrosomes moving outward

Front 8

Pro-metaphase

Back 8

Chromosomes continue to thicken. Spindles extend from centrosomes and bind to kinetichore of centromere

Front 9

Metaphase

Back 9

Chromosomes are pushed to the midline of cell by spindles

Front 10

Anaphase

Back 10

centromere splits, spindles begin to shorten and pull chromosomes apart. Two sister chromatids are now two separate chromosomes

Front 11

Telophase

Back 11

Chromosomes are pulled to opposite ends of the cell. Cell is prepared to divide

Front 12

Mitotic spindle

Back 12

apparatus of spindles that controls chromosome movement during mitosis

Front 13

aster

Back 13

radial array of short microtubules that extends from each centrosome

Front 14

Genetics

Back 14

Scientific study of heredity and genetic variation

Front 15

Heredity

Back 15

The transmission of traits from one generation to the next

Front 16

Variation

Back 16

differences in appearance that offspring show from parents and siblings

Front 17

Genes

Back 17

units of heredity made up of segments of DNA

Front 18

Asexual reproduction

Back 18

two parents give rise to offspring that have unique combinations of genes inherited from the two parents

Front 19

Clone

Back 19

genetically identical individuals from the same parent

Front 20

Sexual reproduction

Back 20

two parents give rise to offspring that have unique combinations of genes inherited from the two parents

Front 21

autosomes

Back 21

The 22 pairs of chromosomes that do not determine sex

Front 22

diploid cell

Back 22

two sets of chromosomes

Front 23

haploid cell

Back 23

single set of chromosomes (gamete)

Front 24

zygote

Back 24

fertilized egg, has one set of chromosomes from each parent

Front 25

Meiosis I

Back 25

results in two haploid daughter cells with replicated chromosomes

Front 26

Meiosis II

Back 26

Results in four haploid daughter cells with un replicated chromosomes

Front 27

synapsis

Back 27

homologous chromosomes loosely line up, aligned gene by gene

Front 28

Crossing-over

Back 28

non-sister chromatids exchange DNA segments

Front 29

Chiasmata

Back 29

X-shaped regions where crossing over occurred

Front 30

Mutations

Back 30

Changes in an organisms DNA, source of genetic diversity

Front 31

hybridization

Back 31

mating two contrasting true breeding variaties

Front 32

P-generation

Back 32

true breeding parents

Front 33

F1 generation

Back 33

hybrid offspring of the p generation

Front 34

F2 generation

Back 34

when F1 generation self-pollinates

Front 35

alleles

Back 35

alternate versions of a gene

Front 36

Law of segregation

Back 36

states that two alleles for a heritable character separate during gamete formation and end up in different gametes

Front 37

monohybrids

Back 37

individuals that are heterozygous for one character

Front 38

dihybrids

Back 38

crossing two true breeding parents differing in two characters

Front 39

Law of independent assortment

Back 39

each pair of alleles segregates independently of each other pair of alleles during gamete formation

Front 40

Complete dominance

Back 40

occurs when phenotypes of the heterozygote and dominant homozygote are identical

Front 41

Incomplete Dominance

Back 41

the phenotype of F1 hybrids is somewhere between the phenotypes of the two parental varieties

Front 42

Codominance

Back 42

two dominant alleles affect the phenotype in separate distinguishable ways

Front 43

Quantitative characters

Back 43

those that vary in the population along a contiunuum

Front 44

polygentic inheritance

Back 44

additive effect of two or more genes in a single phenotype

Front 45

Sex-linked gene

Back 45

Gene located on either sex chromosome

Front 46

Barr body

Back 46

The Inactive X

Front 47

Linked genes

Back 47

genes located on the same chromosome that tend to be inherited together

Front 48

genetic recombination

Back 48

the production of offspring with combinations of traits differing from either parent

Front 49

parental types

Back 49

Offspring with a phenotype matching one of the parental phenotypes

Front 50

recombinants

Back 50

Offspring with non-parental phenotypes

Front 51

Genetic map

Back 51

an ordered list of the genetic loci along a particular chromosome

Front 52

Linkage Map

Back 52

A genetic map of a chromosome based on recombination frequencies

Front 53

Map units

Back 53

Distances between genes

Front 54

non-disjunction

Back 54

pairs of homologous chromosomes that do not separate normally during meiosis

Front 55

Aneuploidy

Back 55

results from the fertilization of gametes in which non disjunction occurred

Front 56

Polyploidy

Back 56

condition in which an organism has two complete sets of chromosomes

Front 57

Inversion

Back 57

reverses a segment within a chromosome

Front 58

Translocation

Back 58

moves a segment from one chromosome to another

Front 59

Semi-conservative model

Back 59

Watson and Cricks idea that when a double helix replicates each daughter molecule will have one old strand and one new strand

Front 60

Origins of replication

Back 60

where the two DNA strands are separated, opening up a replication bubble

Front 61

Replication fork

Back 61

Y-shaped region where new DNA strands are elongating

Front 62

Helicases

Back 62

Enzymes that untwist the double helix at replication fork

Front 63

Topoisomerase

Back 63

corrects "overwinding" ahead of replication forks by breaking swiveling and re-joining DNA strands

Front 64

primase

Back 64

can start an RNA chain from scratch and adds RNA nucleotides one at a time using the parental DNA as a template

Front 65

DNA polymerases

Back 65

catalyze the elongation of new DNA at a replication fork

Front 66

Okazaki Fragments

Back 66

How the lagging strand is synthesized which are joined together by DNA ligase

Front 67

DNA polymerase III

Back 67

synthesizes new DNA by covalently adding nucleotides to the 3' end of a pre existing DNA strand or RNA primer

Front 68

DNA polymerase I

Back 68

Removes RNA nucleotides of primer from 5' end and replaces them with DNA nucleotides

Front 69

mismatch repair

Back 69

repair enzymes that correct errors in base pairing

Front 70

nucleotide excision repair

Back 70

a nuclease cuts out and replaces damaged stretches of DNA

Front 71

Gene expression

Back 71

process by which DNA directs protein synthesis, includes transcription and translation

Front 72

Transcription

Back 72

the synthesis of RNA under the direction of DNA

Front 73

Translation

Back 73

The synthesis of a polypeptide which occurs under the direction of mRNA

Front 74

Ribosomes

Back 74

site of translation

Front 75

primary transcript

Back 75

initial transcript from any gene

Front 76

Triplet-code

Back 76

the flow of information from a gene to protein a series of non-overlapping three nucleotide words

Front 77

template strand

Back 77

provides a template for ordering a sequence of nucleotides in an RNA transcript

Front 78

codons

Back 78

mRNA triplets read in the 5'-3' direction

Front 79

RNA polymerase

Back 79

How RNA synthesis is catalyzed, pries te DNA strands apart and hooks together the RNA nucleotides

Front 80

Transcription factors

Back 80

mediate the binding of RNA polymerase and the initiation of transcription

Front 81

transcription initiation complex

Back 81

A promoter that contains transcription factors and RNA polymerase II

Front 82

TATA box

Back 82

promoter crucial in forming the initiation complex in eukaryotes

Front 83

introns

Back 83

non coding regions

Front 84

exons

Back 84

usually translated into amino acid sequences

Front 85

RNA splicing

Back 85

removes introns and joins eons creating an mRNA molecule with continuous coding sequence

Front 86

tRNA

Back 86

How a cell translates an mRNA message into a protein

Front 87

wobble

Back 87

allows for some tRNAs to bind to more than one codon

Front 88

P site

Back 88

holds the tRNA that carries the growing polypeptide chain

Front 89

A site

Back 89

holds the tRNA that carries the next amino acid to be added to the chain

Front 90

E site

Back 90

exit site where discharged tRNAs leave the ribosome

Front 91

polyribosome

Back 91

A number of ribosomes that can translate into a single mRNA simultaneously

Front 92

Mutations

Back 92

changes in the genetic material of a cell or virus

Front 93

Point mutations

Back 93

changes in just one base pair of a gene

Front 94

base pair substitution

Back 94

replaces one nucleotide and its partner with another pair of nucleotides

Front 95

missense mutations

Back 95

still code for an amino acid but may not be the correct one

Front 96

non sense mutations

Back 96

changes amino acid codon to a stop codon

Front 97

frameshift mutation

Back 97

Insertion or deletion altering the reading frame

Front 98

operator

Back 98

Regulatory switch, usually positioned within the promoter

Front 99

operon

Back 99

entire stretch of DNA that contains the operator promoter and genes that they control

Front 100

repressor

Back 100

How the operon is switched off, blocks RNA polymerase

Front 101

core-repressor

Back 101

molecule that cooperates with a repressor protein to switch an operon off

Front 102

inducer

Back 102

inactivates the repressor to turn the lac operon on

Front 103

CAP catobolite activator protein

Back 103

an activator of transcription subject to control through a stimulatory protein

Front 104

cyclic AMP

Back 104

When glucose is scarce, how CAP is activated

Front 105

histone acetylation

Back 105

acetyl groups attach to positively charged lysine's in histone tails

Front 106

genomic imprinting

Back 106

methylation regulates expression of either the maternal or parental alleles of certain genes at the start of development

Front 107

alternative RNA splicing

Back 107

different mRNA molecules produced from the same primary transcript depending on which RNA segments are treated as exons and introns

Front 108

Proteasomes

Back 108

giant protein complexes that bind protein molecules and degrade them

Front 109

miRNA

Back 109

micro-RNA small single stranded RNA molecules that bind to mRNA

Front 110

RNAi

Back 110

Inhibition of gene expression by RNA molecules caused by small interfering RNAs

Front 111

Transformation

Back 111

New DNA integrated into the bacterial chromosome

Front 112

Conjugation

Back 112

The ability of bacterial cells to exchange DNA through a structure called pili

Front 113

Transduction

Back 113

the movement of DNA from one bacterial cell to another by way of bacteriophage

Front 114

Transposons

Back 114

Fragments of DNA that have the ability to replicate/jump to other areas of a genome

Front 115

Hardy Weinburg Equations

Back 115

Used to determine allele or genotypic frequencies found in a population