Biology Unit 4

Front 1

bacterial DNA replication

Back 1

DNA attached to plasma membrane
DNA replication begins at replication origin
enzymes replicate DNA

Front 2

Eukaryotic DNA vs. bacterial DNA

Back 2

linear vs. circular
eukar. is much longer

Front 3

chromatin

Back 3

DNA and protein

Front 4

nucleosome

Back 4

DNA and 8 histone proteins

Front 5

heterochromatin

Back 5

condensed tightly and never expressed, never uncoils for transcription

Front 6

euchromatin

Back 6

open (able to be expressed) except during cell division

Front 7

G1

Back 7

primary growth phase, doubles in size, organelles and cytoplasm double

Front 8

S phase

Back 8

DNA replicates

Front 9

G@

Back 9

secondary growth phase
special structures needed for cell division form
-chromosomes begin coiling (condensing)
-spindle fibers attach to kinetochore proteins near centromeme region of chromosome

Front 10

Mitosis

Back 10

cell division

Front 11

cytokinesis

Back 11

cell actually pinches in two

Front 12

feedback regulation at 3 checkpoints

Back 12

G1, G2, metaphase

Front 13

CdKs

Back 13

protein kinase that activates numerous cell proteins by phosphorylating them, molecular regulation of cell cycle

Front 14

cyclin

Back 14

proteins that bind to CdKs proteins, activating them

Front 15

sexual reproduction

Back 15

union of gametes (fertilization or syngamy)

Front 16

Meiosis characteristics only

Back 16

-two division instead of one
-synapsis or crossing over (prophase)
-reduction division

Front 17

prophase I

Back 17

-chromosomes condense, nucleus and nucleoli disappear
-synapsis or crossing over occurs between chromatids of adjacent homologous chromosomes

Front 18

metaphase I

Back 18

homologous pairs of chromosomes line up at the equatior (random assortment)

Front 19

anaphase I

Back 19

homologous pairs of chromosomes pull apart, reduction division occurs

Front 20

telophase I

Back 20

new cell has half the amount of chromosomes as the original parent and each chromosomes is different due to crossing over

Front 21

meiosis II

Back 21

exactly like mitosis, but with haploid cells

Front 22

law of segregation

Back 22

during gamete formation, alleles separate. one allele (of the pair) goes to each gamete

Front 23

law of independent assortment

Back 23

which allele goes to which gamete is a random event

Front 24

principle of dominance

Back 24

a dominant trait masks the appearance of a recessive one

Front 25

test cross

Back 25

if you have a dominant phenotype and want to determine the original genotype, always use the homozygous recessive to test it

Front 26

product law

Back 26

the chance that a number of independent events will occur together is equal to the product of the chances that each individual event will occur separately

Front 27

epistasis

Back 27

one gene, in homozygous recessive form, blocks the expression of the dominant gene

Front 28

polygenic

Back 28

two or more genes contribute to the phenotype in an additive way, aka continuous variation (skin pigmentation, human height)

Front 29

pleiotropy

Back 29

one allele can cause more than one phenotype effect.

Front 30

incomplete dominane

Back 30

genotype and phenotype ratios are always the same because the heterozygote genotypes results in phenotypes between the dominant and recessive traits

Front 31

multiple alleles

Back 31

more than 2 alleles (forms a gene takes) exist in a population

Front 32

autosomes

Back 32

body chromosomes or somatic chromosomes, humans have 22 pairs

Front 33

karyotype

Back 33

a map of homologous pairs of chromosomes

Front 34

nondisjunction

Back 34

homologous pairs of chromosomes do not separate properly

Front 35

monosomics

Back 35

loss of an autosome

Front 36

trisomic

Back 36

extra autosome