Bio Unit 4

Front 1

binary fission

Back 1

cell division in prokaryotes
chromosomes attach to plasma membrane at origin of replication
two attachment sites move apart after two copies are made
two daughter cells

Front 2

mitosis

Back 2

interphase - longest phase, G1, S (synthesis), G2 (spindle forms, gets ready to divide)
prophase - chromosomes condense, become visible
prometaphase - only fragments of nuclear membrane
metaphase - centrosomes at opposite poles, centromeres line up at center
anaphase - sister chromatids (exact copies) pulled to opposite poles, karyokinesis: splitting of nuclear content
telophase & cytokinesis - nuclear envelope forms, cleavage furrow, nucleolus forming, splitting of cytoplasm

Front 3

checkpoints

Back 3

G1: cell decides whether or not to divide NO GOING BACK
G2: is the spindle ready for mitosis to happen
M: (metaphase) are the chromosomes lined up properly

Front 4

tumors (3 types)

Back 4

benign - stays contained
malignant - spreads to surrounding areas
metastatic - spreads throughout the body

Front 5

oncogenes vs. proto-oncogenes

Back 5

oncogenes are genes that cause cancer
proto-oncogenes are genes that perform normal cellular function but become oncogenes when something goes wrong

Front 6

SRY gene

Back 6

makes males male
on y chromosome
XX (SRY+) = male
XY (SRY-) = female

Front 7

test cross

Back 7

can distinguish between a homo dominant and a hetero by crossing it with homo recessive

Front 8

dihybrid cross

Back 8

follows two traits simultaneously
9:3:3:1

Front 9

codominance

Back 9

when two alleles are expressed simultaneously, black & white feathers

Front 10

incomplete dominance

Back 10

black + white = gray

Front 11

pleiotropy

Back 11

a change in one gene locus results in multiple changes in the phenotype

Front 12

epistasis

Back 12

when alleles at one locus affect expression of genes at another locus (labs)

Front 13

polygenic traits

Back 13

many traits are the result of the additive effects of many genes
continuous variation (height)

Front 14

ratio in mendelian mono-hybrid crosses

Back 14

3:1

Front 15

ratio in mendelian di-hybrid crosses

Back 15

9:3:3:1

Front 16

mendelian ratios found b/c

Back 16

one allele always fully dominant
trait governed by single locus
no genotypes were lethal
all autosomal
assorted independently

Front 17

hemizygous

Back 17

only one gene
i.e. males are hemizygous for most of the genes found on the x chromosome

Front 18

barr bodies

Back 18

one x chromosome in each female cell shuts off and becomes forms a tight ball

Front 19

law of independent assortment

Back 19

alleles of a gene on nonhomologous chromosomes

Front 20

test cross

Back 20

YyRr x yyrr
to determine things b/c you know one parent will only contribute recessive alleles

Front 21

allele mapping

Back 21

the closer together two genes are on the same chromosome, the less likely there will be crossing over between them
highest recombinant frequency (map distance), further they are apart
assumes crossing over is completely random

Front 22

nondisjunction

Back 22

homologous chromosomes dont separate in meiosis I
OR sister chromatids don't separate in meiosis II
**most often fatal

Front 23

trisome 21

Back 23

downsyndrome = 3 copies of chr 21

Front 24

XXX

Back 24

female
two barr bodies

Front 25

XXY

Back 25

male
1 barr body

Front 26

XO

Back 26

alive
female
b/c x chr is very large

Front 27

YO

Back 27

dead
y chr relatively small
can't survive w/o x

Front 28

other genes

Back 28

located in mitochondria and chloroplasts
-carry their own DNA
inherited from mother only
mutations not lethal b/c so many copies