Honors Bio 2 Unit 3

Chromatin

coiled DNA

DNA

blueprint of life, has instructions for proteins

Gene

sectin of DNA that codes specific proteins exported from nucleus that then code for traits

Monomer of DNA

Nucleotide

how does DNA run?

5’ to 3’

DNA Replication

Easier to copy from template, uses semi-conservative replication

Semi-Conservative

helps reduce number of copy errors with 3 stages

1st stage of semi-conservative replication

unwinding DNA

2nd stage of semi-conservative replication

Base Pairing

3rd stage of semi-conservative replication

DNA Ligase

Unwinding DNA

uses helicase to unwind and unzipe double helix

Base pairing

DNA polymerase runs along parent strand of DNA and bonds free floating nucleotides to create daughter strand

DNA ligase

bonds ladder

Haploid

1 set of chromosomes, all sex cells, have 23 ch

Diploid

2 sets of chromosomes, one set from each parent, gametes combine to 2n (46)

Zygote

Fertilized egg when sperm combines with egg

sister chromatid

replicates itself to form identical copies connected by centromere

Homologus chromosomes

Paired sister chromosomes that have gene for same traits arranged in same order, 1 from mom and 1 from dad

Crossing Over

non-sister chromosomes on homologous pairs exchange genetc segments to make new combos of DNA, important for genetic variation and haploid cells

Structural things about RNA

U instead of T, single strand

Transcription

DNA into RNA that leaves out nucleus pore

translation

RNA to protein/trait, out in cytoplasm

Interphase

chromosomes duplicate, ready for meiosis

Prophase I

Homologous pairs line up to form tetrad and cross over, sister chromosomes pair up 

Metaphase I

Pair line up at metaphase plate

Anaphase I

Homologous pairs seperate

Telophase I

Pairs have seperate from cross

mieosis 2

Seperate chromosomes

mutations

change in order in DNA sequence that might change gene function or order

Mutagen

something that can alter DNA code and cause mutations

2 types of mutagens

point mutations and chromosomal mutations

Point mutation

most common, least drastic, one base altered

Types of Point mutations

substitutions, inversions, insertions, and deletions

Chromosomal mutations

Less common, more drastic, affects entire chromosomes so affects many genes not just 1

Insertion

added sequence inserted somewhere, adds extra proteins

Deletion

part of chromosome missin, missing proteins

Inversion

segment breaks off and flips over, so code may not create same proteins

Translocations

piece breaks off but insert itself elsewhere so gene may not code for correct protein and may have damaged another gene

nondisjunction

chromosomes don’t seperate properly during meiosis and cause extra copies to show up in gamates

Human cells diploid changes due to what?

Nondisjunction

Trisomy

3 copies of chromosomes causing down syncrome/klinefelter syndrom

klinefelter syndrome

47 chromosomes, boy affected, low testerone, underdeveloped muscles

Turner syndrome

45 chromosomes, girls affected, short, slow growth

genetics

study of how traits are passed to offspinrg

Principle of Independent assortment

inheritance of 1 trait has no affect on inheritance of another

alleles

different options for same trait

dominant allele

stronger gene preventing other gene from showing

Recessive allele

doesn’t show even through its present

homozygous/purebreed

Both aleles of pair are same

Heterozygous/hybrid

one dom and 1 recessive allele

Genotype

combo of genes organisms has

Phenotype

PHysical apperance

Punnet Square

predicts possible gene make-up

Test Cross

Cross with homozygous recessive, you finish out recessive triat only if parent is hybrid

Codominant

both alleles expressed

Incomplete dominance

1 allele isn’t totally dominant over toher

Sex-linked

show up in males bc only have 1 X chromosomes, females have 2 so 1 is healthy and genes use only healthy trait

How meiosis produces haploid cell from diploid parents cell

replication occurs once but division happens twice

Where does meiosis occur?

sex cells

Why is meiosis required?

To get correct number of chromosomes in offspring w/ genetic diversity

How does meiosis produce variation?

crossing over, random assortment,