Midterm

Cell cycle

M-phase
-Prophase
-Prometaphase
-Metaphase
-Anaphase
-Telophase
Interphase
-G1
-S, synthesis (2n)
-G2
-G0, no cell division

G1 phase

Gap 1
high gene expression (2n)

G2 phase

Gap 2 (Interphase)
prepares to divide (4n)

M phase

Mitosis
-cell division (2n)

Interphase

Gene expression

S phase

Synthesis
DNA replication occurs (4n)

Mitosis

-somatic cells (body)
2 identical daughter cells

Meiosis

-germ line cells (sex)
4 haploid cells
Meiosis I -homologous chromosomes separate 2n -> n
Meiosis II -sister chromatids separate n -> 1/2n

Meiosis I

Homologous chromosome pairing
Crossing over
Segregation

Meiosis II

Sister chromatid seperation

Prophase

Chromosome condense
Microtubules extend
Nucleolus dissolving

Prophase I

Leptotene -spindle fibers produced
Zygotene -synaptonemal complex
Pachytene -crossing over
Diplotene -tetrads
Diakinesis -moving to metaphase

Metaphase

Chromosome align to metaphase plate
Microtubules connect to kinetochore

Anaphase

Chromosome pull apart
Kinetochore microtubules retract

Telophase

Chromosome condense
Nonkinetochore microtubules elongate cell
Nuclear envelope reforms

Cytokinesis

Nucleolus reforms
plants -cell plate
animal -ring and cleavage furrow

Diploid

products of mitosis
2n

Haploid

products of meiosis
n

Homologous chromosome

2 chromosomes which contain the same genes
-mother
-father

Sister chromatids

copies of the chromosomes made during replication
connected at the kinetochore

Recombination

chromatids are broken and recombined to form a new combination of alleles

Crossing over

homologous chromosomes are recombined to form a new combination of alleles

Independent assortment

alleles get separated and inherited independently of one another

Germ cell

sex cell
-sperm
-ovum

Somatic cell

body cells

Telomere

repetitive DNA sequences at the end of a chromosome
-provide a "cushion" for replication

Disjunction

chromosome seperation

Nondisjunction

failed chromosome separation
-leads to aneuploidy

Aneuploidy

missing or extra chromosomes
-cohesion of chromatids
-connection of homologous
-recombination

Define the study of genetics & explain its significance for applied and curiosity-driven science.

Study of inheritance
-explains the script of life for an organism
-helps us connect evolution within organisms

Relate the sub-disciplines of genetics considered in this course to levels of biological organization.

Transmission Genetics -mendelian genetics, between generations
Evolutionary genetics -genetic relationship of evolution
Molecular genetics -studies DNA and RNA and connects to organisms

Outline the significance and timing of mitosis and meiosis within animal and plant life cycles.

Meiosis -cells for sexual reproduction
Mitosis -replicates non-sex cells, growth and development

Describe the major phases of the cell cycle including those of mitosis and meiosis.

M-phase (I, II)
-Prophase
-Prometaphase
-Metaphase
-Anaphase
-Telophase
Interphase
-G1
-S, synthesis (2n)
-G2
-G0, no cell division

Describe the general structure and normal movement of eukaryotic chromosomes during the cell cycle.

Prophase -condense
Metaphase -middle
Anaphase -separated

List similarities and differences between mitosis, meiosis I and meiosis II.

Mitosis
-2 identical cells (2n)
-somatic cells
-separating sister chromatids
Meiosis I
-2 identical cells (2n)
-germ line cells
-separating homologous pairs
-crossing over
Meiosis II
-4 haploid cells (n)
-germ line cells
-separating sister chromatids

Recognize and draw phases of mitosis, meiosis I, meiosis II, as well as their products.

Describe the consequences and some causes of abnormal chromosome movement during cell division

trisomy 21 -down syndrom

Nucleotide

nucleoside (sugar + base)
phosphate group

DNA

nucleotide (A, T, G, C)
deoxyribose sugar-phosphate backbone

RNA

nucleotide (A, U, G, C)
ribose sugar-phosphate backbone

Purine

A, G
2 ring structure

Pyrimidine

C, T (U)
1 ring structure

DNA replication (including enzymes)

helicase -unwinds helix (breaks H bonds)
DNA topoisomerase -relaxes supercoiling (cutting strand)
SSB -prevents re-annealing
Primase -synthesizes RNA primers
DNA polymerase III -synthesizes DNA (reads 3'-5')
DNA polymerase I -replaces RNA primer with DNA (removes 5'-3')
DNA ligase -joins DNA segments

Leading strand

makes 5'-3'
DNA synthesis continuous

Lagging strand

makes 5'-3'
DNA synthesis discontinuous
-Okazaki fragments

Bacterial Transcription (including enzymes)

Initiation
-RNA polymerase -binds to promoter
Elongation
-core enzyme -syntheiszes RNA
Termination
-intrinsic: hairpin loops (GC), polyU tail slows polymerase
-Rho-dependant: stem-loop, protein binds to RNA (disassociates from polymerase)

Eukaryotic Transcription (including enzymes)

Initiation
-Initial committed complex -TFIID & TATA box
-Preintitaion compex -TFIIE & TFIIH
-RNA Polymerase I -ribosomes
-RNA Polymerase II -mRNA
-RNA Polymerase III -tRNA
Elongation
Termination
-polyA tail -dissociates RNA polymerase from template
-RNase -cuts pre-mRNA off

mRNA

5'-3'
transcription, carries genetic code
(same as coding)
codons for tRNA

Coding strand

5'-3'
Same as mRNA

Template strand

3'-5'
anti-codons for tRNA

5’ cap

added after transcription
protects mRNA from degradation

polyA tail

facilitates transport
protects from degradation
enhances translation by recognition

Intron

do not code for proteins
-removed

Exon

do code for proteins
-remain

Promoter

10 Pribnow box 5'-TATAAT-3'
35 Consensus sequence 5'-TTGACA-3'

RNA coding region

Terminator

Bacteria
-Intrinsic: hairpin, polyU, destabilize
-Rho-dependent: stem-loop, dissociate
Eukaryote
-polyA tail: dissociates

Enhancer

increase gene transcription
-bind to proteins on promoter regions

Silencer

repress transcription
-bind to proteins that bend DNA

Activator

Repressor

List the components of nucleotides and the features of DNA.

nucleotide
-nucleoside, sugar and base (A, U, G, C)
-phosphate group
deoxyribose sugar-phosphate backbone
-phosphodiester bonds (5' phosphate and 3' OH)

Use information on base occurrence to predict overall nucleotide composition.

Compare and contrast transcription in bacteria and eukaryotes.

Bacteria
-cytoplasm
-terminator sequence
-RNA Polymerase
Eukaryote
-nucleus
-posttranscriptional modifications
-RNA Polymerase (I,II,III)

Describe RNA processing in eukaryotes.

splicing and addition of 5' cap and poly-A tail

Amino acid

central a carbon
amino group
carboxyl group
R-group
-peptide bonds

polypeptide

assembled in ribosomes
N5' - C3'

N-terminus

NH3+
start

C-terminus

COOH-
end

Genetic code

3 nucleotides make up the codon
tRNA anticodon matches and brings aa
aa binds with peptide bonds to growing chain

Codon

5'-3'
mRNA

Anti-codon

3'-5'
tRNA

Wobble

3rd base wobble in tRNA
most 3' nucleotides code for the same aa

tRNA

anticodon
brings amino acids to the ribosome

Ribosome

where translation occurs

small subunit -mRNA
P site -holds tRNA
A site -binds molecule
E site -tRNA leave
large subunit -polypeptide chain

Consensus sequence

-35 TTGACA
-10 TATAAT

Start codon

AUG, Met

Stop codon

UAG, UAA, UGA
you are going
you go away
you are away

Open reading frame

no stop codons
between START and STOP

Translation

Polyribosome

Mutation

random
germ-line -passed
somatic -personal

Transition

purine to pyrimidine
A->G
C->T

Transversion

A->C
A->T
G->C
G->T

Mutation levels

Amino Acid -aa
-Synonymous: Leu -> Leu
-Nonsynonymous: Leu -> Gly
RNA level -codons
-Missense: CAA -> AAA
-Silent: CAA -> CAG (same aa)
-Nonsense: UAU -> UAG (aa to stop)
-Nonstop: UAG -> UAU (stop to aa)
DNA level -nucleotides
-Substitutions: transition, transversion
-Frameshift: insertion, deletion

Heritable mutation

germ-line

Non-heritable mutation

somatic

Describe the general structure of amino acids and polypeptides.

Use the genetic code to predict amino acid sequence of polypeptides and amino acid changes resulting from mutation.

Describe the general significance of mutations.

increase variation
affect phenotypes

Describe the translation process including ribosome assembly and role of tRNA’s.

initiator tRNA carries Met to codon
ribosome forms
-IFs control formation and binding of tRNA

small subunit -mRNA
P site -holds tRNA
A site -binds molecule
E site -tRNA leave
large subunit -polypeptide chai

Oogenesis

development of the ovum

Binomial expansion

n = number of events (offspring)
-determine ratio
-divide by total
6 - 6:0, 5:1, 4:2, 3:3, 2:4, 1:5, 0:6

Binomial equation

order doesn't matter
N -number of offspring
X -dominant happens
p -probability dominant happens (<1)
q -probability it doesn't happen (<1)

Chi-square analysis

observed
expected
o-e
(o-e)^2
(o-e)^2/e

DF = phenotypes-1
p > a (0.05) -fail to reject
p < a -rejec

Dominant vs Recessive

r -skips generation
D -doesn't skip
-affected kids always have at least one parent

Autosomal vs Sex-linked

AA -even in sexes
Xr -more males
XD -more females
-all daughters of affected dad
Y -only males

Autosomal recessive

skips generations
both parents have: all kids have
sexes equal

cystic fibrosis
PKU
Sickle-cell anemia

Autosomal dominant

no parent: no kids
affected kid: at least one parent
sexes equal

achondroplasia (dwarfism)
Huntington disease
Marfan syndrome

X-linked recessive

skips generations
affected mom: all sons
affected dad: all daughter, no sons
more males

colour blindness
hemophilia
fragile X syndrome