Bio Unit 3 Genetics

aesexual reproduction

a single organism reproducing without the aid of another.

Mitosis

division of the nucleus

somatic cells

body cells

Gametes

sex cells

Haploid

having a single set of unpaired chromosomes

diploid

2 sets of chromosomes

triploid

3 sets of chromosomes

Genome

all of an organism's genetic material

homologus chromosomes

Chromosomes that have the same sequence of genes and the same structure

Allels

Different forms of a gene

Homozygous

Having two identical alleles for a particular gene

Heterozygous

having two different alleles for a trait

meisosis

makes sex cells

Prophase 1

Crossing over occurs (homologus recombination)

Metaphase 1

chromosomes line up

Anaphase 1

Homologous chromosomes separate

telephase 1

wall in between forms

cytokinesis 1

2 cells form

prophase 2

centrosomes duplicate, spindle already formed

metaphase 2

Chromosomes line up at the equator.

anaphase 2

pull apart

telekinesis/cytokinesis 2

wall forms and seperates

germline

sex cells

how many haploid cells do men produce in Meiosis?

4

how many haploid cells do women produce in Meiosis?

1

Nondisjunction

Error in meiosis in which homologous chromosomes fail to separate.

Aneuploidy

Abnormal number of chromosomes.

Trisomies

3 copies of a chromosome

P generation

true-breeding parents

F1 generation

offspring of the P generation

F2 generation

Offspring resulting from interbreeding of the hybrid F1 generation.

Law of Segregation

pairs of homologous chromosomes separate so that only one chromosome from each pair is present in each gamete

law of independent assortment

states that genes separate independently of one another in meiosis

dominant allele

an allele that is fully expressed in the phenotype of a heterozygote

recessive allele

An allele that is masked when a dominant allele is present

Mendalian traits

genes interact

Epistasis

A gene masking the expression of another

complete dominance

one allele is completely dominant over another

Codominance

both alleles for a gene are fully expressed

incomplete dominance

blended

polygenic inheritance

multiple genes affect a single trait

norm of reaction

range of phenotypes

multifactorial

many factors, both genetic and environmental, influence phenotype

Pedigree

"family tree"

complementary base pairs

A, T, C, G, U

A

Adenine

T

Thymine

C

Cytosine

G

Guanine

U

Uracil

semi-conservative replication

DNA is split to make 2 daughter strands

Helicase

unwinds and unzips DNA

What direction is DNA written?

5' to 3'

What direction is DNA read?

3-5

DNA primase

DNA primer

DNA polymerase

forms new copies of the DNA

leading and lagging strand

leading: 5' to 3'
lagging: 3' to 5'

Okazaki fragments

segments of the lagging strand

DNA ligase

fills in the gaps

Telomeres

DNA at the tips of chromosomes

Telomerase

rebuilds telomeres

protein synthesis

The creation of a protein from a DNA template.

Transcribe

DNA to RNA

Translate

RNA to Protein

mRNA

messenger RNA

tRNA

transfer RNA; carries amino acids to the ribosome)

rRNA

composes the ribosome

Codon

a set of 3 nucleotides on the mRNA

Anticodon

"complementary" 3 nucleotides on tRNA

amino acids

building blocks of proteins

Which codon is start?

AUG

Mutations

a random error in gene replication that leads to a change

deletion mutation

removes a chromosomal segment

duplication mutation

repeats a chromosomal segment

inversion mutation

reverses a chromosomal segment

Translocation mutation

moves a chromosomal segment to another non-homologous chromosome.

point mutation

gene mutation in which a single base pair in DNA has been changed

base-pair substitution

type of mutation in which a single base pair changes

missense mutation

altered codon still codes for another amino acid

nonsense mutation

changes a normal codon into a stop codon

silent mutation

alters a base but does not change the amino acid

base pair intersection

adds or delete a nucleotide set

Frame shift

causes codons to change

bionary fission

the asexual method used by bacteria to reproduce