BIOL 101 Midterm 2

lock in

Where does transcription start?

The promoter

When does the cell split?

Telophase

Interphase

G1, S, G2

G1

The growth of cell & increase in cytoplasmic contents

S phase

DNA is doubled

G2

Growth of cell & increase in cytoplasmic contents

Order of phases in mitosis

Prophase, prometaphase, metaphase, anaphase, telophase

Prophase

Chromatin condensed to form sister chromatids

Prometaphase

Nuclear envelope cracks & spindle fibers attach to sister chromatids

Metaphase

All duplicated chromosomes line up in the middle of the cell

Anaphase

Sister chromatids separate, ends w daughter chromosomes at each end of the cell

Telophase

Daughter nuclei form at the two poles of a cell

Sister chromatids

Duplicated chromosomes staying together

Stimulative system

A “go” signal must be present to replicate

Inhibitive system

A “stop” signal must not be present to replicate

Proto-oncogens

Genes that normally stimulate cell division

Normal system

Inhibitive signals are present on receptor at plasma membrane → relay proteins transduce signal → cell division inhibited

Faulty system

Inhibitive signals are present → relay protein is missing or nonfunctional → excessive cell division

Homologous chromosomes

Same genes with different alleles in meiosis

Diploid cell

Has pairs of homologous chromosomes

Haploid cell

Only has 1 set of homologous chromosomes

Anaphase 1

Homologous chromosomes pulled apart

Anaphase 2

Sister chromatids are pulled apart

Metaphase 1

Homologous chromosomes line up in middle of the cell

Metaphase 2

Sister chromatids line up in the middle of the cell

Crossing over

Prophase 1

Mitosis end result

2 diploid daughter cells

Meiosis end result

4 haploid daughter cells

Law of segregation

Allele pairs segregate from each other during the production of gametes

Males & females equally affected

Autosomal

Affected individuals have unaffected parents

Recessive

How to tell if something is dominant?

Cross it with a heterozygote

To determine if homozygous dominant or heterozygous

Cross with a homozygous recessive

Complete dominance

1 phenotype or another

Incomplete dominance

Blend of the two phenotypes

Codominance

Both phenotypes are expressed

How many alleles per gene?

2

Polygenic

Multiple genes go into one trait

Plieotrophy

1 gene influences multiple traits

When do cells become haploid?

When homologous chromosomes are pulled apart

When do sister chromatids separate

Anaphase 2

2 heterozygous in a dihybrid cross

9:3:3:1

Central dogma

DNA transcription → RNA translation → protein

What does the RNA polymerase bind to

Promoter

What does transcription need to start

AUG

Which was does mRNA run?

5’-3’

mRNA alterations

Add cap, remove introns, splice together exons, poly A tail

Missense mutation

1 nucleotide is changed

Frameshift mutation

1 nucleotide is added or subtracted and the whole protein is shifted

Silent mutation

Change to a nucleotide but no change to amino acid sequence

Nonsense mutation

Change in nucleotide sequence that creates a stop codon too early