LB145Sec 001-004

Today’s Outline

- Announcements:Homework #3 is due on Thursday. Flexible Grade Weightings due TODAY!

Honors option meeting: 8:15-8:45am on Monday (see website)

- Calvin Cycle (a human experiment)- Mendel’s Peas

Fig. 10-17

Light

Fd

Cytochromecomplex

ADP +

i H+

ATPP

ATPsynthase

ToCalvinCycle

STROMA(low H+ concentration)

Thylakoidmembrane

THYLAKOID SPACE(high H+ concentration)

STROMA(low H+ concentration)

Photosystem II Photosystem I4 H+

4 H+

Pq

Pc

LightNADP+

reductaseNADP+ + H+

NADPH

+2 H+

H2OO2

e–e–

1/21

2

3

Light

Fig. 10-5-4

H2O

Chloroplast

LightReactions

NADP+

PADP

i+

ATP

NADPH

O2

CalvinCycle

CO2

[CH2O](sugar)

The Calvin Cycle

Photosynthesis and Mendel3.0

Mendel’s Experiments

• Gregor Mendel – the father of modern genetics.

• Inheritance of traits in pea plants (P. sativum).

• Flower color, seed shape, pod shape, pod color, flower position, stem length, embryo color.

3.1

The Evolution of Wrinkled Peas

Wrinkled peas aren’t just wrinkled…

WrinkledRound

2.1

The Evolution of Wrinkled Peas

They taste good too!

WrinkledRound

2.2

Fact Sheet: Pisum sativum

• Common names: Field peas.• Native to: Near East Iraq,

Turkey, Israel, Palestine, etc.• A key crop of the Neolithic

Agricultural Revolution, oldest recorded samples date to 10,000 BCE.

1.1

Inheritance of Pea Plant Traits• In pea plants, traits are often

controlled by one set of alleles. These alleles can combine in a homozygous (dominant or recessive) or heterozygous fashion depending on parental alleles.

• Examples: – The Round vs. Wrinkled pea trait

is controlled by the alleles R and r– The Yellow vs. Green pea trait is

controlled by the alleles Y and y.

3.3

From Traits to Genes

• Amazingly, Mendel had no knowledge of DNA, genes or chromosomes.

• The traits (alleles) that Mendel described correspond to specific genes within the pea plant genome.

3.5

Molecular Biology: Central Dogma

The “R” allele of the sbe1 gene codes for the SBE1 protein.

The SBE1 protein is an enzyme that converts simple starch (amylose) to complex starch (amylopectin).

How does it all work?

Inside the Pea Cell: Sugar and Starch2.4

Fig. 10-17

Light

Fd

Cytochromecomplex

ADP +

i H+

ATPP

ATPsynthase

ToCalvinCycle

STROMA(low H+ concentration)

Thylakoidmembrane

THYLAKOID SPACE(high H+ concentration)

STROMA(low H+ concentration)

Photosystem II Photosystem I4 H+

4 H+

Pq

Pc

LightNADP+

reductaseNADP+ + H+

NADPH

+2 H+

H2OO2

e–e–

1/21

2

3

Light

Fig. 10-5-4

H2O

Chloroplast

LightReactions

NADP+

PADP

i+

ATP

NADPH

O2

CalvinCycle

CO2

[CH2O](sugar)

The Calvin Cycle

Inside the Pea Cell: Sugar and Starch

Calvin Cycle

Glyceraldehyde 3-phosphate

2.4b

Inside the Pea Cell: Sugar and Starch

G3P

Fructose 1,6-biphosphate

Fructose 6-phosphate

Glucose 6-phosphate

Glucose 1-phosphate

ADP-Glucose

Fruc

tose

bip

hosp

hate

al

dola

se

Fruc

tose

bip

hosp

hase

Hexo

se-p

hosp

hate

iso

mer

ase

Phos

phog

luco

mut

ase

ADP-

gluc

ose

phos

phor

ylas

e

2.4c

Inside the Pea Cell: Sugar and Starch

ADP-Glucose

Amylose

Amylopectin

Starch synthetase

Starch branching enzyme

2.4d

Starch-branching enzyme

Sucrose

The Evolution of Wrinkled PeasWrinkled peas aren’t just wrinkled…

they taste good too!

Wrinkled(r allele of sbe1 gene)

Round(R allele of sbe1 gene)

2.1

G3P

(Intermediates)

Amylose

Amylopectin

G3P

(Intermediates)

Amylosenon-functioning starch branching enzyme

Sucrose

functioning starch branching enzyme

Question: What do seed shape and seed taste have in common?

- Wrinkled peas are wrinkled because they have a higher water content than round peas. When they dry, round peas retain their shape while wrinkled peas do not due to water loss.

Think and Write Down an Answer: - Why would wrinkled (sweet) peas have a higher

water content than round (starchy) peas?

Discuss your answer with your neighbor (2 mins)- Name cards will be used to find out what your team thought.

2.9

In Detail: The Genetics ofRound and Wrinkled Peas

4.0

…. SEE LB145

UNIT 3

The Artificial Selection ofRound and Wrinkled Peas

5.0

Artificial Selection of Sweet Peas

• Wrinkled peas are sweeter and in ancient times farmers tended to select them for breeding.

5.1

Artificial Selection:

• Consider two fields with pea plants.• Some plants produce wrinkled peas, others produce

round peas (50% wrinkled peas, 50% round peas).

5.2

Artificial Selection:

• Question: assuming you were a farmer and could weed out wrinkled peas or round peas, would it be easier to create a permanent monoculture of round peas or a permanent monoculture of wrinkled peas?

5.3

Artificial Selection:• From a mixed field, what is easier to facilitate

through artificial selection?

(a) Monoculture of (dominant) round peas.

(b) Monoculture of (recessive) wrinkled peas.

(c) Both scenarios have equal difficulty.

5.4

Darwin and Selection• Darwin used the example

of artificial crop selection as an example to support his theory of natural selection.

5.5

For THURSDAY:1. Homework #3 – the Photo Problem2. StudyNotes 4 is due on Tuesday Feb 12th.