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Unit 3. Genetics. Gregor Mendel. Austrian Monk 1800’s Observed some traits disappeared in one generation, only to reappear in the next Hypothesis: Some traits are stronger than others. Experimental Design Needed something which could be easily manipulated.

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Unit 3 l.jpg

Unit 3

Genetics


Gregor mendel l.jpg
Gregor Mendel

  • Austrian Monk 1800’s

  • Observed some traits disappeared in one generation, only to reappear in the next

  • Hypothesis: Some traits are stronger than others.

  • Experimental Design

    • Needed something which could be easily manipulated.

    • Something with a variety of visible characteristics.


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Gregor Mendel

http://www.youtube.com/watch?v=MWkFxWXHTnw&playnext_from=TL&videos=c5-UkltqOnI


Mendel chose the garden pea l.jpg
Mendel Chose the Garden Pea

  • Quick generation time

  • Does not require much space

  • Peas undergo self-fertilization

    • Pollinate themselves

  • Could also pry open petal to make specific crosses between plants.

  • Many visible traits:

  • Flower color

  • Seed color

  • Seed shape

  • Plant height


Mendel s experimental design l.jpg
Mendel’s Experimental Design

  • Parental Generation

    • For each trait studied he wanted a true breeding plant to begin the experiment.

      • True BreedingGeneration after generation breeds true to a single visible trait.

  • Experiment

    • Cross two different parental generation plants (each One displays One version of the trait)

    • Parental white flower x purple flower cross them and plant the seeds to get the first generation

  • Recorded The Numbers & Traits Of All Generations

    • F1—First Filial (Latin for son/daughter) all purple 100%.

    • Allowed F1 to self-fertilize.

    • Counted the F2 for number of each trait.

    • 75% purple, 25% white.


Mendel s experiment l.jpg
Mendel’s Experiment

  • In this cross Mendel used Parental Tall (TT) and short (tt)

  • All the F1 generation plants were Tall

  • These F1 plants self fertilized to produce the F2 plants

  • The F2 generation had 75% Tall and 25% short


Terminology l.jpg
Terminology

  • Allele – different versions of a trait

    • Example: Pea plants have white or purple flowers.

    • White and Purple are different alleles for the trait of flower color

  • Genotype – the sum of all alleles in an individual

  • Phenotype – the physical representation of the genotype (what the individual looks like)


Terminology8 l.jpg
Terminology

  • Homozygous – the two alleles for a given trait are the same in an individual

    • In our flowers PP homozygous purple or pp homozygous for white

  • Heterozygous – the two alleles for a given train are different in an individual

    • In our flowers Pp heterozygous for flower color purple


Terminology9 l.jpg
Terminology

  • Dominant – the allele expressed as the phenotype in a heterozygote individual

    • Denoted by using the upper case of the letter for the trait

    • The Pp plant will be Purple

  • Recessive – the allele not expressed in a heterozygote

    • Denoted by using the lower case of the letter for the trait

    • The lower case p denotes the recessive white allele


Terminology examples l.jpg
Terminology Examples

  • Pea plants have either white or purple flowers

    • P – purple p – white

  • Purple is dominant to white

  • A purple plant can be homozygous

    • PP for flower color

  • OR heterozygous

    • Pp for flower color


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Terminology Examples

  • A white flower plant must be homozygous (pp) for flower color

    • The recessive trait will only be seen as the phenotype when the individual has two copies of that recessive allele


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Meiosis

  • Specialized cell division for sexual reproduction

  • Results in the production of haploid gametes

  • Each gamete will have a single copy of each gene


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Determining Possible Gametes

  • Start with the genotype of each parent

    • Parent 1 PP; Parent 2 pp

    • Each of parent 1’s gametes will contain 1 P

    • Each of parent 2’s gametes will contain 1 p

Parent 1 Gametes

Parent 2 Gametes

P

P

p

p


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Determining Possible Gametes

  • The parental generation cross between these two plants PP x pp will result in all progeny being Pp

    • They will be phenotypically purple

    • They are all heterozygous for flower color

Pp


Determining possible gametes15 l.jpg
Determining Possible Gametes

  • These first generation (F1) plants will then self fertilize to create the second (F2) generation

  • Start with the genotype of each parent

    • Parent 1 Pp; Parent 2 Pp

    • Half of parent 1’s gametes will contain P the other half will contain p

    • Half of parent 2’s gametes will contain P the other half will contain p

P

p

P

p


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Punnett Squares

  • Graphical representation of each parents gametes

  • Allows for prediction of possible progeny for a given set of parents

  • Determine the gametes of the parents

  • Arrange the gametes on a grid to predict the genotypes and phenotypes of the next generation




Punnett squares19 l.jpg

Fill in the boxes of the parental gametes from the top down through the boxes

Punnett Squares

P

p

P

P

p

P

p

p


Punnett squares20 l.jpg

Fill in the boxes of the parental gametes from the side across through the boxes

Punnett Squares

P

p

P

P

P

P

p

P

p

p

p

p


Punnett squares21 l.jpg

The interior of the boxes now has the possible genotypes of the progeny from this parental cross of Pp x Pp

Punnett Squares

P

p

P

P

P

P

p

P

p

p

p

p


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Genotypically the progeny from this parental cross of Pp x Pp

25% Homozygous Purple

50% Heterozygous Purple

25% Homozygous White

Phenotypically

75% Purple

25% White

Punnett Squares

P

p

Homozygous

Heterozygous

P

P

P

P

p

Purple

Purple

Heterozygous

Homozygous

P

p

p

p

p

White

Purple


Test cross l.jpg
Test Cross the progeny from this parental cross of Pp x Pp

  • Used to determine an unknown individual’s genotype.

  • Cross unknown with a known homozygous.

  • Which homozygous? A dominant or recessive? … see next slide for answer


Test cross24 l.jpg
Test Cross the progeny from this parental cross of Pp x Pp

  • *Homozygous Recessive!

    • Allows you to deduce the genotype by offspring produced.

    • If any offspring are recessive then the unknown must have been Heterozygous.

    • If all offspring are dominant the unknown purple plant is homozygous dominant


Test cross25 l.jpg
Test Cross the progeny from this parental cross of Pp x Pp

  • You found a purple pea plant …

    • Is it homozygous or heterozygous for flower color?

  • Test cross is with a white pea plant

If it is homozygous

purple

If it is heterozygous

purple


Two factor crosses l.jpg
Two Factor Crosses the progeny from this parental cross of Pp x Pp

  • A two factor cross looks at two different traits at the same time for example seed shape (round or wrinkled) AND plant height (tall or short)

  • Set up is the same for the punnett square

  • Keep the alleles for each trait together in the boxes!!


Two factor crosses27 l.jpg
Two Factor Crosses the progeny from this parental cross of Pp x Pp

  • Peas can be either round (R) or wrinkled (r)

  • Plants can be tall (T) or short (t)

  • A plant can be homozygous for either or both of these traits (RRTT, RRtt, rrTT,rrtt)

    • round tall, round short, wrinkled tall, wrinkled short

  • A plant can be heterozygous for either or both of these traits (RrTt, RRTt, RrTT,)

    • round tall for all of them


Two factor crosses28 l.jpg
Two Factor Crosses the progeny from this parental cross of Pp x Pp

  • We’ll cross two double heterozygous plants (RrTt x RrTt)

  • Each gamete will have one allele of each trait

  • The gametes produced by each of these individuals are as follows

    • RT

    • Rt

    • rT

    • rt


Two factor crosses29 l.jpg

R the progeny from this parental cross of Pp x Pp

R

T

T

t

t

r

r

R

t

R

T

T

r

t

r

Two Factor Crosses

  • Arrange the gametes of one parent across the top of the grid

  • Arrange the gametes of the other parent down the side of the grid


Two factor crosses30 l.jpg

R the progeny from this parental cross of Pp x Pp

R

R

R

R

R

R

R

R

R

T

T

T

T

T

T

T

T

T

T

t

t

t

t

t

t

t

t

t

t

r

r

r

r

r

r

r

r

r

r

Two Factor Crosses

  • Fill in the boxes with the gametes from the top down through the boxes

R

t

R

T

T

r

t

r


Two factor crosses31 l.jpg

R the progeny from this parental cross of Pp x Pp

R

R

R

R

R

R

R

R

R

T

T

T

T

T

T

T

T

T

T

t

t

t

t

t

t

t

t

t

t

r

r

r

r

r

r

r

r

r

r

R

R

R

R

R

t

t

t

t

t

R

R

R

R

R

T

T

T

T

T

T

T

T

T

T

r

r

r

r

r

t

t

t

t

t

r

r

r

r

r

Two Factor Crosses

  • Fill in the boxes with the gametes from the side across through the boxes


Two factor crosses32 l.jpg
Two Factor Crosses the progeny from this parental cross of Pp x Pp

  • Determine all of the possible phenotypes and genotypes for the progeny


Two factor crosses33 l.jpg

Phenotypes the progeny from this parental cross of Pp x Pp

Round and Tall

Round and Short

Wrinkled and Tall

Wrinkled and Short

Genotypes

Round / Tall

RRTt

RrTt

RRTT

Round / Short

RRtt

Rrtt

Wrinkled / Tall

rrTT

rrTt

Wrinkled / Short

rrtt

Two Factor Crosses


Standard dominance l.jpg
Standard Dominance the progeny from this parental cross of Pp x Pp

  • In the heterozygote, the dominant allele is expressed as the phenotype

  • Purple flower color is dominant to white

    • A Pp plant will be purple


Incomplete dominance l.jpg
Incomplete Dominance the progeny from this parental cross of Pp x Pp

  • The heterozygote individual has a phenotype in between the two phenotypes

  • Flower color of roses

    • R red

    • r white

      • RR = red

      • Rr = pink

      • Rr = white


Incomplete dominance36 l.jpg
Incomplete Dominance the progeny from this parental cross of Pp x Pp

  • RR x rr

  • F1 all Rr = pink

  • Cross the F1s Rr x Rr

  • F2

    • 25% Red

    • 50% Pink

    • 25% White


Codominance l.jpg
CoDominance the progeny from this parental cross of Pp x Pp

  • Neither allele is dominant

  • Heterozygote expresses both alleles equally

  • In flowers a red and white flower

  • ABO blood groups


Codominance38 l.jpg
CoDominance the progeny from this parental cross of Pp x Pp

  • There are 3 alleles for blood type

    • IA – A

    • IB – B

    • i – O

  • Each person has 2 alleles

  • The combination of the 2 alleles determines the individual’s blood type


Codominance39 l.jpg
CoDominance the progeny from this parental cross of Pp x Pp

  • Phenotype A has 2 possible genotypes

    • IA IA

    • IA i

  • Phenotype B has 2 possible genotypes

    • IB IB

    • IB i

  • Phenotype O has only 1 possible genotype

    • ii


Codominance40 l.jpg
CoDominance the progeny from this parental cross of Pp x Pp

  • If mom is IA IA and dad is IB IB all of their children will be type IA IB

  • If mom is IA i and dad is IBi what are the possible blood types of their children?


Codominance41 l.jpg
CoDominance the progeny from this parental cross of Pp x Pp

Set up a punnett square as normal with mom’s alleles across the top and dad’s alleles down the side

A

I

i

B

I

i


Codominance42 l.jpg

A the progeny from this parental cross of Pp x Pp

A

A

I

I

I

B

B

B

I

I

I

CoDominance

Fill in the boxes as before

i

i

i

i

i

i


Codominance43 l.jpg

Genotypes the progeny from this parental cross of Pp x Pp

AB

Bi

Ai

ii

Phenotypes

AB

B

A

O

i

A

A

A

I

I

I

i

B

B

B

I

I

I

i

i

i

i

CoDominance


Codominance44 l.jpg
CoDominance the progeny from this parental cross of Pp x Pp

  • Questions to ponder

    • Female blood type A, Male blood type AB

      • What blood type(s) is/are not possible for their children?

    • Male blood type O

      • What blood type(s) is/are not possible for their children?


Codominance45 l.jpg
CoDominance the progeny from this parental cross of Pp x Pp

  • Questions to ponder

    • Female blood type A, Male blood type AB

      • What blood type(s) is/are not possible for their children? … type O is not possible

      • Because Dad is AB he does not have a copy of the recessive i to pass down to any of his children

    • Male blood type O

      • What blood type(s) is/are not possible for their children? … type AB is not possible

      • To have blood type O Dad must be homozygous ii so all of his children will get one copy of i from him thus AB blood type is not possible


Epistasis l.jpg
Epistasis the progeny from this parental cross of Pp x Pp

  • Two genes are required to produce a particular phenotype

  • We will study coat colors of Labrador retrievers


Epistasis47 l.jpg
Epistasis the progeny from this parental cross of Pp x Pp

  • The interaction of 2 genes determine coat color

  • Pigment

    • B = Black, b = Brown

  • Deposition

    • E = yes, e = no

    • whether the pigment can be integrated into the fur


Epistasis48 l.jpg
Epistasis the progeny from this parental cross of Pp x Pp

  • Black Labs

    • Must have at least one B and one E

      • BBEE, BBEe, BbEE, BbEe

  • Brown or chocolate Labs

    • Must have 2 bb and at least one E

      • bbEE, bbEe

  • Yellow Labs

    • Are homozygous recessive for deposition ee

    • They cannot put the pigment into their fur

      • BBee, Bbee, bbee


Examples l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • What are the genotypes of the Brown and Black parents who only produce Black and Yellow puppies?

  • First determine what you know about the genetics of the parent dogs and their puppies


Examples50 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • You know the black lab parent has at least one B allele and one E allele B_E_

  • You know the brown parent must be homozygous for brown pigment because it is recessive bb and that the pigment is deposited so at least one E so it is bbE_


Examples51 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • The black puppies have at least one B and one E

  • The yellow puppies must be homozygous recessive for deposition (ee) but you don’t know what their pigment alleles are


Examples52 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • Parents: B _ E _ x bbE _

  • Puppies: B _E _ and _ _ ee

    • Remember the question is what are the genotypes of the parents …


Examples53 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • Parents: B _ E _ x bbE _

  • Puppies: B _E _ and _ _ ee

  • To have any yellow puppies, each parent must have a recessive (e) allele to give

  • To not have any brown puppies, all puppies must be receiving a dominant B


Examples54 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • Parents: B B E e x bbEe

  • Puppies: B _E _ and _ _ ee

    • The red indicates the alleles you figured out!

    • The black dog parent must be homozygous because there were no brown puppies

      When we set up the punnett square we see we’re right …


Examples55 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • Parents: B B E e x bbEe

    • Gametes: BE, Be and bE, be

B

E

B

e

b

E

B

b

E

E

B

b

E

e

b

B

b

E

e

B

b

e

e

e


Examples56 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • Parents: B B E e x bbEe

    • Gametes: BE, Be and bE, be

B

E

B

e

b

E

B

b

E

E

B

b

E

e

Black

Black

b

B

b

E

e

B

b

e

e

e

Black

Yellow


Examples57 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • What are the genotypes of the Brown and Yellow parents who only produce Black and Yellow puppies?

  • First determine what you know about the genetics of the parent dogs and their puppies


Examples58 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • You know the yellow lab parent must be homozygous recessive for deposition (ee)

  • You know the brown parent must be homozygous for brown pigment because it is recessive bb and that the pigment is deposited so at least one E (bbE_)


Examples59 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • The black puppies have at least one B and one E

  • The yellow puppies must be homozygous recessive for deposition (ee) but you don’t know what their pigment alleles are


Examples60 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • Parents: _ _ ee x bbE _

  • Puppies: B _E _ and _ _ ee

    • Remember the question is what are the genotypes of the parents …


Examples61 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • Parents: _ _ ee x bbE _

  • Puppies: B _E _ and _ _ ee

  • To have any yellow puppies, each parent must have a recessive (e) allele to give

  • To not have any brown puppies, all puppies must be receiving a dominant B


Examples62 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • Parents: BB ee x bbEe

  • Puppies: B _E _ and _ _ ee

    • The red indicates the alleles you figured out!

      When we set up the punnett square we see we’re right …


Examples63 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • Parents: B B e e x bbEe

    • Gametes: BE, Be and bE, be

B

B

e

e

b

E

B

b

E

e

B

b

E

e

b

B

b

e

e

B

b

e

e

e


Examples64 l.jpg
Examples the progeny from this parental cross of Pp x Pp

  • Parents: B B e e x bbEe

    • Gametes: BE, Be and bE, be

B

B

e

e

b

E

B

b

E

e

B

b

E

e

Black

Black

b

B

b

e

e

B

b

e

e

e

Yellow

Yellow


Environmental factors influence gene expression l.jpg
Environmental Factors Influence Gene Expression the progeny from this parental cross of Pp x Pp

  • Gene products are proteins.

  • Proteins are affected by temp, PH, salt concentration, etc.

  • Some gene products appear differently in different environments.


Environmental gene interaction l.jpg
Environmental Gene Interaction the progeny from this parental cross of Pp x Pp

Winter

Coat

Summer Coat

  • Artic Fox

  • Protein production (Pigment) temperature regulated.

  • WarmProduce pigmentBrown.

  • ColdNo pigmentWhite.


Environmental gene interaction67 l.jpg
Environmental Gene Interaction the progeny from this parental cross of Pp x Pp

  • Siamese Cat

  • Cooler areas produce pigment.

  • Ears/nose & extremities.

  • If cat gets obese the layer of fat will insulate the skin from the body heat, entire cat will now be pigmented.


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Genetic Issues the progeny from this parental cross of Pp x Pp

  • Recessive does not denote good … Dominant does not denote good

    • Perfect VisionRecessive

    • Huntington’s diseaseDominant

  • Meiosis can make errors in gamete formation


Meiotic error non disjunction l.jpg
Meiotic Error Non-Disjunction the progeny from this parental cross of Pp x Pp

  • The failures of chromosomes to separate during Anaphase I or II.

  • Results in one gamete with too many chromosomes & one gamete with too few.


Non disjunction examples l.jpg
Non-Disjunction Examples the progeny from this parental cross of Pp x Pp

Down’s Syndrome: Trisomy 21

  • Individual has three copies of chromosome 21.

  • More common in older mothers.

  • Males produce sperm throughout their physically mature lifetime

  • Females are born with all their eggs.

  • Eggs are stalled at the end of meiosis I.

  • Upon physical maturity, 1-2 eggs per month complete meiosis, two are ovulatedOlder mothers….older eggs. Any damage accumulates over the life-time and can result in non disjunction in meiosis 2.

  • Nondisjunction In Sex Chromosomes

    • Can occur in both male and females.

    • XXX Sterile female

    • XXY Sterile male

    • XYY Fertile male

    • X Sterile female

    • Y Non viable


Dominant diseases l.jpg
Dominant Diseases the progeny from this parental cross of Pp x Pp

  • Huntington’s disease is a dominant progressive neurological disorder resulting in death

  • How many alleles are required for Huntington’s disease?

  • How many alleles are required for a recessive disorder?


Dominant diseases72 l.jpg
Dominant Diseases the progeny from this parental cross of Pp x Pp

  • Huntington’s disease is a dominant progressive neurological disorder resulting in death

  • How many alleles are required for Huntington’s disease?

    • It’s dominant so you only need one allele to have the disorder

  • How many alleles are required for a recessive disorder?

    • Recessive traits are only expressed if the individual is homozygous so you need 2 alleles, one from each parent


Disease terminology l.jpg
Disease Terminology the progeny from this parental cross of Pp x Pp

  • Autosomal

    • Trait is on one of the 22 pairs of non-sex chromosomes

    • These traits are inherited equally among males and females

  • Sex Linked

    • Trait is on either the X or Y chromosome

    • These traits are inherited differently based on the person’s gender

  • Carrier

    • individual has one copy of the recessive allele but is not afflicted by the disease

    • There are no carriers for dominant traits


Sex linked traits l.jpg
Sex Linked Traits the progeny from this parental cross of Pp x Pp

  • These traits are encoded on the X or Y chromosomes

  • The gender of the individual is linked to the expression of these traits

  • Sex Chromosomes X, Y

    • XX=Female

    • XY=Male.

  • Male sperm carry either X or Y determines gender of offspring.

  • Female eggs only carry an X for sex chromosome.

  • Since female have two X chromosomes, they follow standard dominance patterns for genes carried on X chromosome.

    • Females cannot inherit genes on the Y chromosome because they don’t have a Y chromosome

  • Males only have one X chromosome.

  • Any genes on their one chromosome are automatically expressed.


Sex linked traits75 l.jpg
Sex Linked Traits the progeny from this parental cross of Pp x Pp

http://www.youtube.com/watch?v=H1HaR47Dqfw&playnext_from=TL&videos=wNlPLX5yjQE


Pedigrees l.jpg
Pedigrees the progeny from this parental cross of Pp x Pp

Males

Normal

Carrier

Afflicted

Females


Pedigrees77 l.jpg
Pedigrees the progeny from this parental cross of Pp x Pp

Horizontal Line

Represents Marriage

Carrier Dad

Carrier Mom

Vertical Line Down

to their children

Normal

Son

Afflicted

Daughter

Carrier

son


Pedigree example l.jpg
Pedigree Example the progeny from this parental cross of Pp x Pp

This is an autosomal recessive disorder

?

What is the father’s most probable genotype?


Pedigree example79 l.jpg
Pedigree Example the progeny from this parental cross of Pp x Pp

This is an autosomal recessive disorder

Dd

DD

DD

Dd

DD

Dd

What is the father’s most probable genotype?

Mom is a carrier, they have 2 normal kids and two

Carriers … from this information dad is most probably

normal


Pedigree example80 l.jpg
Pedigree Example the progeny from this parental cross of Pp x Pp

This is a sex linked recessive disorder

?

What is the father’s most probable genotype?


Pedigree example81 l.jpg
Pedigree Example the progeny from this parental cross of Pp x Pp

This is a sex linked recessive disorder

XcX

XcY

XcY

XcXc

XY

XcX

What is the father’s most probable genotype?

A daughter is afflicted. Since this is sex linked and recessive

We know that dad must be afflicted because the daughter received

a recessive X from each of her parents.


How do our genes make us who we are l.jpg
How do our genes make us who we are? the progeny from this parental cross of Pp x Pp

  • Genes are the construction plans for proteins

  • DNA transcribed into RNA (Single stranded)

    • Called mRNA—Messenger RNA

  • Ribosomes can only read mRNA


Transcription l.jpg
Transcription the progeny from this parental cross of Pp x Pp

http://www.youtube.com/watch?v=vJSmZ3DsntU&playnext_from=TL&videos=g_7DQONcg2I


Transcription84 l.jpg
Transcription the progeny from this parental cross of Pp x Pp

  • RNA Polymerase

    • Enzyme which reads DNA & makes the mRNA copy.

    • mRNA copy made by complimentary base pairing to the DNA

    • Binds to promoter at the beginning of each gene

    • Read DNA one base at a time

  • Transcription

    • RNA Polymerase binds to promoter

    • Reads one base at a time synthesizing single stranded mRNA from the DNA template

    • mRNA transported to the cytoplasm through the nuclear pores


Translation l.jpg
Translation the progeny from this parental cross of Pp x Pp

http://www.youtube.com/watch?v=1NkLqjQkGHU&playnext_from=TL&videos=aJ9DK01wG2U


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The Genetic Code the progeny from this parental cross of Pp x Pp

  • DNA 4 bases

    • Adenine, Thymine, Guanine, Cytosine

  • RNA 4 bases

    • Adenine, Uracil, Guanine, Cytosine

  • 20 Amino Acids (A.A,).

    • How to specify each individual A.A.

    • Use a distinct, unique set of 3 bases.

    • Called a codon.

    • Each A.A. is coded for by at least one codon.

    • Special codons.

      • Start/F metheonine: AUG

      • Stop: UAA, AAG, UGA


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The Codon Table the progeny from this parental cross of Pp x Pp


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Find AUG the progeny from this parental cross of Pp x Pp

The first letter of the codon is A … So you know you start with A as the

First Position


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Find AUG the progeny from this parental cross of Pp x Pp

The second letter of the codon is U … So you know you’ve narrowed it down

To these 4 with the Second Position


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Find AUG the progeny from this parental cross of Pp x Pp

The third letter of the codon is G … So you now you know it is

Met (methionine) or start if it’s the first codon of the sequence


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Translation the progeny from this parental cross of Pp x Pp

  • Protein synthesis

    • Ribosomes read the mRNA.

    • Assemble A.A. in order by reading one codon at a time.

  • How do the A.A. get to the ribosomes?

    • tRNA—Transfer RNA

    • Molecules which bring A.A. to ribosomes.

    • Has Anti codon at one end to temporarily base pair to mRNA.

    • Has corresponding A.A. at other end


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Translation Steps the progeny from this parental cross of Pp x Pp

  • Initiation

    • Small ribosome subunit binds to mRNA at start codon AUG.

    • Large subunit then binds to complex.


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Translation Steps the progeny from this parental cross of Pp x Pp

  • Elongation

    • Ribosome moves down mRNA one codon at a timeadding one amino acid at a time.

    • tRNA comes in and binds by complimentary base pairing.

    • Peptide bond is formed between the new amino acid and the peptide chain

    • Continues down mRNA until stop codon reached.

    • Transfer RNA only carries specific A.A.


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Translation Steps the progeny from this parental cross of Pp x Pp

  • Termination

    • Stop codon; signal the two ribosome subunits to break apart

    • Completed protein released


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Genetic Control the progeny from this parental cross of Pp x Pp

  • Regulation Of Gene Expression

  • Differentiation requires that some of our genes be turned on or off in specific cells.

  • Remember, each and every cell has Full set of DNA.

  • Cells express different genes according to their functions.


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Genetic Control the progeny from this parental cross of Pp x Pp

  • Repressors

    • Prevents transcription.

    • Bind over Promoter.

    • Blocks RNA ploymerase from binding.

  • Activators

    • Increase rate of transcription.

    • Bind upstream of Promoter.

    • Assist RNA polymerase in binding to DNA.


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DNA / RNA and Genetic Control the progeny from this parental cross of Pp x Pp

http://www.youtube.com/watch?v=BGtNZwd3brg&playnext_from=TL&videos=1Ihv5jV0kjs


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