ANSC 3121 Exam 1

Gene

Unit of hereditary traits

Chromosome

protein and DNA carrying genetic information within the genes

mitosis

division of sematic cells

gametes

haploid sex cells

meiosis

division of cells to create gametes, haploid

alleles

alternate form of a gene

genotype

genetic make up of an organism

genome

all of the possible alleles that are within a population

phenotype

the physical expression of the genotype

Law of Segregation

2 alleles separate during meiosis, each sperm or egg cell can unite with any other egg or sperm cell, random chance creates mix of alleles resulting in variety of offspring

Law of Independent assortment

alleles of one trait have no effect on the transmission of alleles of other traits

Multiplication Rule

(AND) two + independent events, the probability that they will occur at the same time

Addition Rule

(OR) two + mutually exclusive events, the probability that either will occur

Interphase G1

gap, when gene expression is occurring, creating proteins

Interphase S

synthesis, when 2nd copy of chromosomes is made, DNA synthesis

Interphase G2

gap, preparing for M phase

Non-disjunction

chromosomes don't separate

x-linked genes

genes located on x chromosome

incomplete dominance

heterozygote is a blend of both alleles

codominance

heterozygote reveals distinct expression of both alleles

lethal mutations

cause death at early age

sex-related expression

expression altered or influenced by gender

sex-linked

gene is on either X or Y chromosome

sex limited

expression is specifically limited to one sex

sex influenced

sex influences the expression, usually influenced by hormones

Pleiotropy

one mutation has many effects on phenotype

synthetic genes

lie on the same chromosome

genetic linkage

tendency of DNA sequences that are close together on a chromosome to be inherited together during the meiosis phase

recombination

occurs at size of chiasmata during meiosis, results in daughter cell chromosomes different from parental chromosomes

r<50%

genes present on same chromosomes, they are linked

r>50%

located on non-homologous chromosome or far apart on homologous chromosomes, independent assortment

two-point test cross

cross between an individual heterozygous at two loci and an individual homozygous for recessive alleles at those loci

double crossovers

detectable if a three point cross is used, the effect of a double crossover is to interchange the middle pair of alleles between homologous chromosomes

Three-point test cross

double crossovers result in switching of the middle gene

factors affecting r/linkage maps

age, environment, gender, nutrition

epistasis

gene interaction, more than one gene affects the same trait

complementary gene action

9:7

Duplicate gene interaction

15:1

Dominant gene interaction

9:6:1

Recessive epistasis

12:3:1

Dominant suppression

13:3

replisome

proteins and enzymes that conduct whole process of prokaryotic DNA replication

DNA A

binds replication site and cleaves H bond

DNA B

Helicase untwists the helix and hydrolyze H bonds of helix

Topoisomerase

release tension, break through phosphodiester bonds and releases the tension and then reattaches it

Primase

RNA Polymerase- adds complimentary RNA bases (U not T)

DNA Polymerase

adding DNA bases and and attach DNA Nucleotides to RNA primer

Telomeres

nucleotides on the end of each DNA strand, repetitive nucleotides that are never expressed, in every S phase we lose telomeres and DNA shortens

Polymerase Chain Reaction (PCR)

chunks of DNA copied, automated process