fit bio 1010 exam 3 review

8/10/2019 FIT BIO 1010 Exam 3 Review

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Chapter 11Cellular Signaling

Cells must signal to each other and interpret the signals they receive

from other cells and the environment Signals are ussually chemicals

The same small set of cell signaling mechanisms shows up in diverse

species and processes (conserved strategies)

Definitions

KinaseEnzyme that catalyzes phosphorylation

LigandA signal molecule

Secondary MessengerIntracellular signals


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Local vs Long distance signaling


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Intercellular receptor


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Signal Transduction - Phosphorylation cascade


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Cells can respond to signals differently

Signalingmolecule

Receptor

Relaymole-

cules

Response 1 Response 2 Response 3 Response 4 Response 5

Cell A: Pathway leadsto a single response. Cell B: Pathwaybranches, leading to

two responses.

Cell C: Cross-talkoccurs between two

pathways.

Cell D: Differentreceptor leads to a

different response.

Activation

or inhibition


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CAMPBELL

BIOLOGYReece Urry Cain Wasserman Minorsky Jackson

2014 Pearson Education, Inc.

TENTH

EDITION

CAMPBELL


TENTH

EDITION

12The Cell Cycle

Lecture Presentation by

Nicole Tunbridge and

Kathleen Fitzpatrick


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The Cell Cycle.

Interphase90% of cell cycle, this is when cell grows- G1& G2 phases are gap phases

- S phase (synthesis) is when DNA is replicated

Mitotic phasewhen cell actually divides

-Mitosisdivision of the nuclear material

-Cytokinesis is the division of the cytoplasm


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Figure 12.12-4

Chromosome

replication

begins.

Two copiesof origin

E. co li cell

Origin of

replication

Cell wall

Plasma

membrane

Bacterial

chromosome1

2 Origin OriginOne copy of the

origin is now at

each end of the

cell.

3

Two daughter

cells result.

4

Replication

finishes.


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How do we organize information transfer (DNA)

Eukaryotic chromosomes made of chromatin

Chromatin iscomplex of DNA and protein Chromatin condenses during cell division into chromosomes

Number of chromosomes is specific for every species

Somatic cells(nonreproductive cells) 2 sets of chromosomes

Gametes(reproductive cells: sperm and eggs) have half as

many chromosomes as somatic cells


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Mitosis


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Cytokinesiscell splitting


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Do cells just randomly move through these stages?


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The Cyclin-dependent kinases (Cdk) Cyclins are proteins expressed in G1

They bind to Cdk proteins

Cdk proteins are activated


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CAMPBELL



TENTH

EDITION

CAMPBELL


TENTH

EDITION

13Meiosis and

Sexual Life

Cycles





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Reproduction

Living organisms distinguished by reproduction

Hereditytransmitting traits from one generation to the next

Variationthe differences in appearance between offspring,parents, and siblings

GeneticsThe scientific study of heredity and variation.

Genes The fundamental unit of heredity made of DNA segments

The location of a gene along a chromosome is its locus

The gene for a trait is usually found on the same locus.

Below are sister chromatids (identical chromatids)


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Distribution of genes in biology

Somatic cellsnon-reproductive/DIPLOID

Gametesreproductive cells (sperm and egg)/HAPLOID

Haploid: 1 copy of the chromosome (1n)

Diploid: 2 copies of each chromosome (2n)

Human somatic cells have 23 distinct chromosomes for a total

of 46 (2x23=46)


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Terminology for chromosomes


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Determining gender

The sex chromosomes,determine thesexof the

Human females have a homologous pair of X chromosomes (XX)

Human males have one X and one Y chromosome (XY)

The remaining 22 pairs of chromosomes are the autosomes


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Asexual reproduction

Asexual reproductionsingle individual passes genes to

offspring without fusion of gametes

Clonesgenetically identical individuals from same parent


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Sexual reproduction

Sexual reproductiontwo parents give rise to offspring with unique

combinations of genes inherited from both parents.

Genes are passed between generations through gametes

Gametesreproductive cells (haploid)

Fertilizationthe union of gametes

Zygotea fertilized egg with one set of chromosomes from each gamete


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Meiosis I and IImaking gametes


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Introduction of genetic diversity

Crossing over (Recombination)

Independent assortment


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Blended InheritanceAn old ideaWhen gametes fuse (fertilization) the traits blend

together and the original traits are lost.

Eventually all members of a species would be exactly the same!

Inheritance would actually work AGAINST speciation (making new species)

Wh t i th h t d h t i th


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What is the character and what is the

trait for each one?

How are traits passed on to their descendents?

GeneThe unit of heredity. (carries the information for a

polypeptide or RNA) responsible for a trait(s).

AlleleAlternate forms of gene that leads to different traits.

GeneticsThe study of heredity

HeredityThe passing of traitsacross generations

Character (eye color) vs Traits (blue or brown)


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How can alleles be different?!?!?


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Gregor MendelFather of Genetics

Mendel discovered the basic principles of heredity bybreeding garden peas in carefully planned experiments


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Experimental design/nomenclature Mated 2 contrasting, true-breeding varieties -hybridization

True-breeding parents - P generation

Hybrid offspring of P generation - F1generation F1individuals pollinate w/other F1hybrids - F2generation

Ovulewhere the eggs are stored

PistilReceptacle for pollen

StamenWhere pollen is generated and released


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Traits do not blend.

Particulate inheritanceGametes fuse (fertilization) and one trait will manifest

but the other remains intact. Must be physically distinct elements

D i /R i i


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Dominant/Recessive traitsMendels Law of Dominance

One allele is dominant and when present will always be manifested.

HomozygousOnly one allele (SS or ss)HeterozygousTwo different alleles (Ss or sS)

PhenotypeWhat is expressed

GenotypeWhat is stored in the code

How does a recessive trait ever get unmasked?


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Mendels Law of Segregation

During meiosis each gamete

receives one allele

H d di i i h b


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How do you distinguish between

homozygous dominant and heterozygous?

What about multiple traits?


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What about multiple traits?

Mendels Law of Independent Assortment

traits sorts independently of one another.


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I l t d i


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Incomplete dominance

M lti l All l


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Multiple Alleles

Pl i t 1 lti l ff t


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Pleiotropy1 gene = multiple effects

Gene for white eyes in

Drosophila make flightmuscles defective.


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ID genetic material Hershey and Chase


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ID genetic materialHershey and Chase

Additi l E id Ch ff R l


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Additional EvidenceChargaffs Rules

1950 - Erwin Chargaff (Chargaffs rules) reported that:

In any species the number of A and T bases are equaland the number of G and C bases are equal

The total number of bases between species may vary.

Watson and Crick


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Watson and Crick

Models for DNA replication


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Models for DNA replication

Messelsson and Stahl test the model


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Messelsson and Stahltest the model

DNA R li i A Cl L k


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DNA Replication:A Closer Look

The copying of DNA is remarkable in speed and accuracy

~6 billion base pairs in humans (1400 bio textbooks) Speed is ~50 nucleotides per second

Accuracy is 1 mistake per 10 billion base pairs

More than a dozen enzymes and other proteins participate

in DNA replication

Figure 16.12


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Origin of

replication

0.5m

0.2

5m

Bacterial

chromosome

Two daughter

DNA molecules

Replication

bubble

Parental (template)

strandDaughter

(new) strand

Replicationfork

Double-

stranded

DNA molecule

(a) Origin of replication in an E. coli cell (b) Origins of replication in a eukaryoticcell

Origin of

replication Eukaryotic chromosome

Double-stranded

DNA molecule

Parental (template)

strand

Daughter (new)strand

Replication

forkBubble

Two daughter DNA molecules

Figure 16.14

New strand Template strand


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5 53

3

5 5

New strand Template strand

SugarPhosphate Base

OH

A T

C

C

G

G

A

C

Nucleotide

DNApoly-

merase

OH

Pyro-phosphate

2 P i

P iP

3

3

A T

C

C

G

G

A

C

T

Leading strand synthesis


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Leading strand synthesis

Lagging strand synthesis discontinuous


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Lagging strand synthesis - discontinuous

Figure 16.17


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Overview

5

3

Laggingstrand

Leading

strand

Leading

strand

Lagging

strandLeading strand

Leading strand

template

Origin of

replication

Overall directions

of replication

5

3

53

5

5

3

33

Single-strand

binding proteins

Helicase

Parental

DNA

DNA pol III

Primer

Primase

Lagging

strand

Lagging strand

template

DNA pol III

DNA pol I5

DNA ligase

123

4

5


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R li ti th E d f DNA M l l


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Replicating the Ends of DNA Molecules

Limitations of DNA polymerase create problems for linear DNA of

eukaryotic chromosomes

The usual replication machinery provides no way to complete the 5ends,so repeated rounds of replication produce shorter DNA molecules with

uneven ends

Not a problem for prokaryotes, most of which have circular chromosomes

Eukaryotic chromosomal DNA molecules have special nucleotidesequences at their ends called telomeres

Telomeres postpone the erosion of genes near the ends of DNA molecules

Shortening of telomeres may be connected to aging

An enzyme called telomerase catalyzes the lengthening of telomeres ingerm cells

Chapter 17: From Gene to Protein


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Chapter 17: From Gene to Protein

The information content of genes is in the specific nucleotide sequence

The DNA inherited by an organism leads to specific traits by dictating

the synthesis of proteins. (ex: enzymes that make flowers purple)

Proteins are the links between genotype and phenotype

Gene expression, the process by which DNA directs protein synthesis,

includes two stages: transcription and translation

Central dogma: information flows from DNARNAProteins

Transcription and Translation


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Transcription and Translation

DNA


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A C C A A A C C G A G T

ACTTTT CGGGGT

U G G U U U G G C CU A

SerGlyPheTrp

Codon

TRANSLATION

TRANSCRIPTION

Protein

mRNA 5

5

3

Amino acid

DNAtemplatestrand

5

3

3

Figure 17.5Second mRNA base


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Third

mRNAbase

(3

endofcodon)

FirstmRNAbase

(5

endofcodon)

UUU

UUC

UUA

UUG

Phe

Leu

Leu

Ile

Val

CUU

CUC

CUA

CUG

AUU

AUC

AUA

AUG

GUU

GUC

GUA

GUG

UCU

UCC

UCA

UCG

CCU

CCC

CCA

CCG

ACU

ACC

ACA

ACG

GCU

GCC

GCA

GCG GAG

GAA

GAC

GAU

AAG

AAA

AAC

AAU

CAG

CAA

CAC

CAU

Ser

Pro

Thr

Ala

Glu

Asp

Lys

Asn

Gln

His

Tyr Cys

Trp

Arg

Ser

Arg

Gly

GGG

GGA

GGC

GGU

AGG

AGA

AGC

AGU

CGG

CGA

CGC

CGU

UGG

UGA

UGC

UGUUAU

UAC

UAA

UAG Stop

Stop Stop

Met or

start

U

C

A

G

U

C

A

G

U

C

A

G

U

C

A

G

U C A G

G

A

C

U

Transcription overview


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p. -

Promoter Transcription unit

RNA polymeraseStart point

1

Template strand of DNARNA

transcript

Unwound

DNA

RewoundDNA

RNAtranscript

Direction of

transcription(downstream)

Completed RNA transcript

Initiation

Elongation

Termination

2

3

5

3

5

5

3

5

3

5

3

5

5

3

3

5

3

3

5

3

5

3

Termination


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Termination

Bacteria: RNA poly. stops transcription at the terminatorand the mRNA

can be translated without further modification

In eukaryotes, RNA poly. transcribes thepolyadenylation signal

sequence; the RNA transcript is released 1035 nucleotides past this

polyadenylation sequence. This must get processed.


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Exons, Domains, and Activity.


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Exons, Domains, and Activity.

Different domains on a protein can have different roles.

By swapping domains between proteins you can engineer activity

The Ribosome


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Initiation


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1 2

P site

3

Largeribosomalsubunit

Translation initiation complex

Large ribosomal subunitcompletes the initiationcomplex.

Small ribosomal subunit bindsto mRNA.

mRNA binding site

Smallribosomalsubunit

InitiatortRNA

Start codon35

E A

35

GTP GDP

P i+

3 5

5

U A C

GA U

mRNA

Elongation Amino end

of polypeptide


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of polypeptideCodon

recognition1

3

5

E

P Asitesite

E

P A

mRNA

GTP

Pi

23GTP

Pi

GDP +

GDP +

Translocation

E

P A

Peptide bond

formation

E

P A

Ribosome ready fornext aminoacyl tRNA

Termination of Translation


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31 2

Releasefactor

3

55

3

Stop codon(UAG, UAA, or UGA)

Ribosome reaches a

stop codon on mRNA.

Release factor

promotes hydrolysis.

Ribosomal subunits

and other components

dissociate.

Freepolypeptide

3

5

2 GTP

2 GDP + 2 P i

How does a ribosome find the ER?


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Protein

ER

membraneSignal

peptideremoved

SRP receptor

protein

Translocation complex

ER LUMEN

CYTOSOL

SRP

Signal

peptide

mRNA

Ribosome

Polypeptide

synthesisbegins.

SRP

binds tosignalpeptide.

SRP

binds toreceptorprotein.

SRP

detachesandpolypeptidesynthesisresumes.

Signal-

cleavingenzyme cutsoff signalpeptide.

Completed

polypeptidefolds intofinalconformation.

1 2 3 4 5 6

So how do errors in processing lead to mutations?


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So how do errors in processing lead to mutations?

Substitutions, additions, or deletions of even one base pair can make a big difference


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Missense mutationsdifferent codon AND different AA


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Additions or deletions can result in a frameshift mutation


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CAMPBELL

BIOLOGYCAMPBELL

BIOLOGY


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TENTH

EDITIONBIOLOGYReece Urry Cain Wasserman Minorsky Jackson

TENTH

EDITION

18Regulation

of Gene

Expression




Regulating the rate of transcription


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Operator regulation of gene expression


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A sequence of DNA in promoter (the operator) binds activator or repressor proteins

The DNA containing the promoter, operator, and gene is called an operon.

Tryptophan is a corepressor which binds to a repressor protein.

The trpOperon


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The trpOperon


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The lacOperon


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Alternative splicing


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CAMPBELL

BIOLOGYCAMPBELL

BIOLOGY


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TENTH

EDITIONBIOLOGYReece Urry Cain Wasserman Minorsky Jackson

TENTH

EDITION

19Viruses




Virus


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Virus- an infectious particle consisting of nucleic acids packaged in a

protein coat (with or without a membrane)

Cannot reproduce or carry out metabolism outside of a host cell

Alive? Not alive?

Genomes


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Viral genomes may consist of either

Double- or single-stranded DNA or RNA

A DNA virus or RNA virus

The genome is either a single linear orcircular molecule of the nucleic acid

Viruses have between three and several

thousand genes in their genome

Genomes


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Membranes can be derived from host cells


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Lytic cycle1 Attachment


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2 Entry of phageDNA and

degradationof host DNA

3 Synthesis of viralgenomes andproteins

4 Self-assembly

5 Release

Phage assembly

Head Tail Tailfibers

Prions


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Slow-acting, virtually indestructible infectious

proteins that cause brain diseases in mammals

Scrapie in sheep, mad cow disease, Creutzfeldt-Jakob disease, Kuru, glaucoma, certain diabeties

all caused by prions

fit bio 1010 exam 3 review

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