bio exam 3

asexual reproduction

1 parent, identical off spring

sexual reproduction

2 parents, genetic variation

prokaryotic chromosomes

1 circular chromosome

eukaryotic chromosomes

multiple linear chromosomes

prokaryotic cell division

binary fission

eukaryotic cell division

mitosis/meiosis

what are sister chromatids

identical copies of a chromosome

Interphase: G1 phase

growth

Interphase: S phase

replication

Interphase: G2 phase

prep for division

Mitosis: Prophase

chromosomes condense

Mitosis: Metaphase

line up in the middle

Mitosis: Anaphase

Separate

Mitosis: Telophase

nuclei reform

Cytokinesis in plants

cell plate

Cytokinesis in animals

cleavage furrow

How is cell division controlled

check points

What causes cancer

uncontrolled division

What is the difference between benign and malignant tumors

benign stays localized and malignant spreads

What does it mean if a tumor undergoes metastasis

it spreads

What are homologous chromosomes

same genes, different alleles

somatic cells

body cells(skin,muscle,nerve),

Diploid 2n, two sets of chromosomes

made by mitosis

used for growth, repair, and everyday body functions

do not directly participate in reproduction

sex cells (gametes)

sperm, eggs

haploid (n), one set of chromosomes

made be meiosis, germ-line cells

fertilize to form a zygote

diploid cells (2n)

contains two sets of chromosomes ( one from each parent)

in somatic cells

46 chromosomes in humans

restored at fertilization

haploid cells (n)

one set of chromosomes

found in gametes

23 chromosomes

mitosis

1 division, identical diploid cells

meiosis

2 division, haploid gametes

Genetic variation

crossing over/ independent assortment

Karyotype

chromosome display (humans: 23 pairs, 46 total)

Nondisjunction

chromosomes fail to seperate

Down syndrome

extra chromosome 21

Chromosome changes

deletion, duplication, inversion, translocation

true breeding

organisms that always produce offspring identical to themselves when self fertilized

they are homozygous for the trait (PP, pp)

“pure line”

hybrids

offspring produce by crossing two true breeding parents with different traits

heterozygous (Pp)

mixed alleles

P generation (parental generation)

original true breeding parents used in a genetic cross

Ex) ppxPP

starting parents

F1 generation

offspring of P generation

F2 generation

offspring produced when F1 individuals self fertilize or are crossed with each other

Connection between gene and allele

gene is the category and allele are the options within the category

Homozygous

two identical allele for a gene

PP or pp

Heterozygous

two different alleles for a gene

How does this relate to the idea of homologous chromosomes?

Homologous chromosomes are pairs—one from each parent—that carry the same genes at the same loci, but they may carry different alleles.

locus/loci

specific physical location of a gene on a chromosome

dominant allele

expressed whenever it is present

mask the recessive allele

recessive allele

expressed only when homozygous

masked by a dominant allele

genotype

genetic make up

PP,pp,Pp

phenotype

physical expression of the genotype

genotype types

homozygous dominant: PP

homozygous recessive:pp

Heterozygous:Pp

law of segregation

alleles separate during gamete formation

each gamete gets one allele

explains why offspring inherit one allele from each parent

law of independent assortment

genes on different chromosomes assort independently

purpose of a test cross

determines whether an organisim with a domincat phenotype is homozygous dominant or heterozygous

pleiotropy

one gene influences multiple traits, sickle cell ex) organ damage, sickled red blood cells, and resistance to malaria

linked genes

genes are located close together on the same chromosome

tend to be inherited together

do not follow independent assortment

recessive

trait shows only when homozygous recessive, cystic fibrosis

dominant

trait shows the one dominant allele, Huntington’s

incomplete dominance

heterozygote=blended phenotype, pink snapdragon

codominance

both alleles fully expressed, AB blood type

pleiotropy

one gene—> many traits, sickle cell

polygenic inheritance

many genes—> one traits, height/skin color

sex link (x linked)

gene on X chromosome, color blindness

Snapdragon flower color

incomplete dominance

RR-red

Rr-pink

rr-white

Human ABO blood group

IA and IB are codominant

i is recessive

Human height

polygenic inheritance

many genes contribute, continuous variation

sickle cell disease

recessive (ss=disease)

heterozygote advantage (Ss= malaria resistance)

monohybrid

examines one trait

dihybrid crosses

examines two traits

what is the monomer of nucleic acids DNA and RNA

a nucleotide

what are the 3 components of the monomer

phosphate group, sugar, and nitrogenous base

what are the nitrogenous bases

DNA: adenine (a), thymine (t), cytosine (c ), guanine (g)

RNA: adenine (a), uracil (u), cytosine (c ), guanine (g)

compare/contrast the monomer composition and structure of DNA with that of RNA

similarity: made of nucleotides (same monomer), share 3 bases (A,C,G), phosphate group, sugar, nitrogenous base

differences:

DNA- sugar(deoxyribose), (A,T,C,G), double helix, more stable

RNA- sugar (ribose), single stranded, less stable/ can leave nucleus

what does it mean to be semiconservative

during DNA replication, each new DNA molecule contains one original parent and one newly made strand

role of DNA polymerase in DNA replication

builds new DNA strands during replication

role of DNA ligase in DNA replication

enzyme that joins DNA fragments together during replication

complementary strand for: ACGCATCGACTA

TGCGTAGCTGAT

Recognize the steps of transcription

1-initiation: RNA polymerase binds to the promotor region of DNA, DNA strands unwind

2-Elongation: RNA polymerase builds mRNA by adding complementary RNA nucleotides

3-termination: RNA polymerase reaches a stop signal, mRNA strand is released and DNA rewinds

name of enzyme that assembles mRNA

RNA polymerase

Provide the sequence mRNA for the following

strand of DNA: ACGCATCGACTA.

UGCGUAGCUGAU

What modifications happen to the primary mRNA transcript in a eukaryote?

5’ cap is added, poly-a tail is added 3’ end, RNA splicing

Contrast exons with introns.

exons-coding regions of a gene, stay in mRNA after processing, used to make the final protein

introns- noncoding regions, removed during RNA splicing, do not code for protein

what is the role of mRNA

acts as a messenger between DNA and ribosomes, carries a codon sequence, provides the template for protein synthesis (translation)

what is the tole of tRNA

helps build proteins during translation, carries amino acids, matches anticodon to the mRNA codon

what is the role of ribosomes in protein synthesis

read the mRNA codons, help match tRNA anticodons to mRNA, link amino acids together to form a polypeptide

Recognize the steps of translation.

Which codon serves as the “start codon”

what amino acid does it code for?

What is the purpose of a “stop codon?”, how many are there

What IS the genetic code?How does it work?

Can a codon code for more than one amino acid?

Trace the processes of translation, transcription, and protein folding.

Contrast the terms mutation and mutagen

What are examples of mutagens?

Recognize the importance of gene expression regulation to cellular metabolism and cellular

differentiation.

Can neighbor cells influence each other’s gene expression?

Describe how prokaryotic genes are turned on and off in response to environmental changes.

Describe an operon.

Recognize a description of DNA packing.

What is a nucleosome?

Contrast reproductive cloning and therapeutic cloning.

Contrast adult stem cells and embryonic stem cells.

What is an oncogene?

What is a carcinogen?