Bio 111 exam 3

DNA, BioMolecules, Gene

meiosis

cell division that produces reproductive cells in sexually reproducing organisms

mitosis

cell division in which the nucleus divides into nuclei containing the same number of chromosomes

Synapsis

the side by side pairing of homologous maternal and paternal chromosomes at the start of meiosis

crossing over

the interchange of sections between pairing homologous chromosomes during the prophase of meiosis

Tetrads

homologous chromosome pairs

chiasmata

x-shaped regions where crossing over occured

Causes of Genetic Variation

1) Mutations
2)Behavior of chromosomes during meiosis
3)Random Fertalization

The Central Dogma

DNA>RNA>Protein

Law of Segregation

the homologous chromosomes separate into different gametes during meiosis

Law of independent assortment

genes on non-homologous chromosomes are inherited independently

testcross

heterosygous with homozygous recessive

Linked genes

teo genes that are close enough on the same gene that they are typically inherited together

Complete dominance

occurs when the phenotypes of the heterozygote and the homozygous dominant are identical

incomplete dominance

phenotype of heterozygote is a hybrid of the dominant and recessive

codominance

two dominant alleles affect the phenotype in separate ways

epistasis

a gene at one locus alters the phenotypic expression of a gene at a second locus

polygenic inheritance

an additive effect of two or more genes on a single phenotype

quantitative characters

characteristics that vary in a population over a continuum

multifactorial characters

genetic and environmental factors influence phenotype

pedigree

colored in shapes are the affected individuals, have the phenotype of the characteristic we are considering

dominant trait in pedigree

two affected parents can have an unaffected child, but two unaffected parents cant have an affected child

Sex-linked traits

if the gene is on an X or Y chromosome instead of an autosome

Amino acid monomers

building block of proteins along with carboxyl and amino groups and side chains (R-groups)

Nucleic Acids

Monomers of DNA and RNA, made of nitrogenous base, a pentose sugar, and a phosphate group

peptide bonds

covalent bonds that link nucleotides

Nitrogenous base pairing

A=T
C=G
(A=U in RNA)

DNA always has

3' and 5' end indicated by whatever the last molecule is (pentose sugar=3'; phosphate group= 5')

transcription

DNA>RNA, RNA polymerase unzips and copies DNA into single stranded RNA

mRNA

messenger RNA, codes for proteins

rRNA

ribosomal RNA, form ribosomes, catalyze protein synthesis

tRNA

transfer RNA, adaptors between mRNA and amino acids, carry amino acids at one end and anticodons at other end

snRNA

small nuclear RNA, function in nuclear processes

translation

RNA>Protein, ribosomes read the mRNA and tRNA codons to string together amino acids into a peptide

Anticodon

a three-letter nucleotide sequence to code for amino acid

Regulation of Transcription

1. Activators
2. Chromosome condensation
3. Degradation of mRNA
4. Regulation of Translation
5. Protein Degradation

Chromosome Condensation

condensed chromosomes are not accessible to RNA polymerase

Regulation of Translation

slow rate of mRNA bind to or move through ribosome

Protein Degredation

Destruction or removal of proteins that are unnecessary