BIOL 3010 Exam 1

Law of Segregation

two alleles from each parent separate during gamete formation and then unite at random

Law of Independent Assortment

different pairs of alleles segregate independently from one another during gamete formation

Complications of Independent Assortment

alleles don’t always assort independently of one another because of linkage

Linkage

the phenomenon where particular alleles of genes tend to travel together during vertical or horizontal gene transfer

Griffith Experiment

Why are heat-killed S and R strains together deadly when apart they aren’t?

Avery and MacLeod Experiment

DNA is primary for transformation

Purines

Adenine and Guanine

Pyrimidines

Thymine and Cytosine

Nucleoside

Sugar with base attached at 1’

Nucleotide

Nucleoside with phosphate attached at 5’

Phosphodiester Bonds

link nucleotides into long chains

Hershey and Chase Experiments

DNA is the transforming agent, not protein

used radioactive sulfurs and phosphorus

Transformation

ability to change the genetic characteristics of an organism

gene

segment of DNA that carries the instructions for building one or more molecules that help cells function

Major and Minor Grooves

Result from vertical displacement of the 2 backbones

Major role of mitosis

make sure sister chromatids are split and segregated equally

sister chromatids

the two identical copies of a chromosome that exist immediately after chromosome replication

centromere

site of kinetochore assembly, where spindle microtubules attach

kinetochore

a specialized chromosomal structure composed of DNA and proteins that is the site at which chromosomes attach to the spindle fibers.

Mad2

spindle checkpoint protein that inhibits the anaphase promoting complex (APC)

Cohesion complex

How sister chromatids are held together

Roberts Syndrome

Caused by mutations in the cohesion complex from defects in mitotic chromatid pairing

meiosis

increases genetic diversity through independent assortment/alignment

synaptemal complex

protein structure that physically connects homologous chromosomes together during meiosis on top of cohesion complexes

recombination nodules

structures that appear during prophase I. An exchange of parts between nonsister chromatids occurs here

chiasmata

x-shaped connection visible between paired homologous chromosomes during meiosis

bivalent

4 chromatid structure formed during meiosis, consisting of a duplicated chromosome tightly paired with its homologous duplicated chromosome

nondisjunction

event occurring occasionally during meiosis in which a pair of homologous chromosomes fails to separate so that the resulting germ cell either has too many or too few chromosomes

Spo11

enzyme responsible for creating the necessary DNA breaks that initiate recombination

Holliday Junction

interlocked regions of two nonsister chromatids in recombination intermediates

Dmc1

helps the invading strand of the non sister chromatid in recombination

CENP-A

kinetochore assembly location

Shugosin

protein added to cohesion during meiosis I to keep sister chromatids together during the first stage

Hunt and Morgan Experiments

Wildtype and mutant fly experiments to prove recombination

Cyclin B

peaks during the G2 to M transition; triggers mitosis

p53

becomes active when DNA is damaged; can induce apoptosis

Cyclin D

peaks in G1 phase

What is a purine?

double ring structure

What is a pyrimidine?

single ring structure

Allele

alternative forms of a single gene

PCR

a fast and inexpensive method of replicating a DNA sequence in vitro when short sequences at each end are known; based on reiterative DNA synthesis that amplifies the products of each previous round of replication

Locus

a designated location on a chromosome; sometimes refers to a gene

Tumor Supressors

inhibit cell cycle progression

Cyclin E

peaks during S phase

Cyclin A

peaks during G2 phase