1. Unit 5 and 6 – Cell Signaling and Cell Cycle
Watch the following Bozeman Biology Episodes (Others under Unit 3)
028 - Cell Cycle, Mitosis & Meiosis Mendelian Genetics Advanced Genetics
032 - Signal Transmission  Genotypes & Phenotype
036 - Evolution of Cell Communication Cell Communication Signal Transduction in Pathways

2. Cell Cycle

4. Relay molecules in a signal transduction pathway
Overview of cell signaling
EXTRACELLULAR
FLUID
Receptor
Signal
molecule
Relay molecules in a signal transduction pathway
Plasma membrane
CYTOPLASM
Activation
of cellular
response
Figure 11.5
Reception 1
Transduction 2
Response 3

5. Example of Pathway Steroid hormones bind to intracellular receptors
(testosterone)
EXTRACELLULAR
FLUID
Receptor
protein
DNA
mRNA
NUCLEUS
CYTOPLASM
Plasma
membrane
Hormone-
receptor
complex
New protein
Figure 11.6 1
The steroid
hormone testosterone
passes through the
plasma membrane.
Testosterone binds
to a receptor protein
in the cytoplasm,
activating it. 2
The hormone-
receptor complex
enters the nucleus
and binds to specific
genes. 3
The bound protein
stimulates the
transcription of
the gene into mRNA. 4
The mRNA is
translated into a
specific protein. 5

6. Other pathways regulate genes by activating transcription factors that turn genes on or off
Reception
Transduction
Response
mRNA
NUCLEUS
Gene P
Active
transcription
factor
Inactive
DNA
Phosphorylation
cascade
CYTOPLASM
Receptor
Growth factor
Figure 11.14

7. Action Potential – salty banana Here is the white-boarding activity we did! 4 Minute action potential
START HERE - RESTING POTENTIAL (Includes multiple other steps)
Na+ is high outside the cell
K+ is high inside the cell
The cell is polarized (negative on the inside and positive on the outside)
A signal is received
Na+ channels open
Na+ diffuses into the cell
K+ channels open
K+ diffuses outside the cell
Depolarization (May include multiple steps)
ACTION POTENTIAL (Includes multiple other steps)
Na/K pump - pumps Na+ OUT and K+ into the cell
Repolarization (Reset) (May include multiple steps)
Action potential moves to the axon terminus
Ca++ channels open
Ca++ moves into the cell
Vesicles with neurotransmitters move to synaptic membrane
Neurotransmitters diffuse from presynaptic axon through synapse
Neurotransmitters bind at postsynaptic membrane (dendrite) of another nerve cell
END HERE The signal is restarted

8. Unit 6 – Meiosis and genetics
Crossing over
4 daughter cells all genetically different
Sodaria lab
Genetics
Monohybrid cross, dihybrid cross, allele, homozygous heterozygous, sex-linked, linked genes, F1, F2, incomplete dominance, codominance

9. Overview of meiosis I.P.M.A.T.P.M.A.T 2n=4 interphase 1 prophase 1
metaphase 1
anaphase 1
n=2
prophase 2
metaphase 2
anaphase 2
telophase 2
telophase 1

10. Alteration of chromosome number
error in Meiosis 1
error in Meiosis 2
all with incorrect number
1/2 with incorrect number

13. No Recombination Asci 4:4

14. Genetics problems
Start assuming genes are on different chromosomes – independent assortment
Other options
Sex-linked
Linked genes
Codominace
Multiple alleles
Others?

15. A different % in male and female = sex linked
XRXR
XrY
XRXr
XRY Xr Y XR Y  XR XR
XRXr
XRY
XRXR
XRY
BINGO! XR Xr
XRXr
XRY
XRXr
XrY
100% red females
50% red males; 50% white males
100% red eyes

16. Linked Genes
Linked genes are found close to each other on the SAME chromosome
Linked genes do not assort independently of each other

19. X-inactivation & tortoise shell cat
2 different cell lines in cat

20. Fruit Fly Genetics – assume simple Mendelian genetics (separate chromosomes
Cross a recessive fly (mutant for both traits) with a fruit fly that is heterozygous for both A = wild type wings (normal) a = mutant wings (vestigial) B = wild type color (yellow) b = mutant color (black)

21. 25% Each

22. How the heck does this happen with the same cross
How the heck does this happen with the same cross? AaBb x aabb A = wild type wings (normal) a = mutant wings (vestigial) B = wild type color (yellow) b = mutant color (black)
Expected
Observed
Wild Type (normal wings/yellow 50 33
Mutant (vestigial wings/black)
Vestigial Wings, Yellow 17
Normal, Black Body

23. CROSSING OVER – 34% are recombinants

24. Chi-square (from Unit 1 review)
Dihybrid Cross with two plants RrYy x RrYy
R = round r = wrinkled
Y = yellow y = green
Write a null hypothesis:
The following are the observed results: complete the chi-square test to determine if the results support your null hypothesis:
Round Yellow Peas
Round Green Peas
Wrinkled Yellow Peas
Wrinkled Green Peas
219 81 69 31

25. Expect a 9:3:3:1 Ratio!

26. Find the full explanation at this link
Phenotype
Observed (O)
Expected (E)
O – E
(O – E)2
Round Yellow Peas
219
225 -6 36
Round Green Peas 81 75 6
Wrinkled Yellow Peas 69
Wrinkled Green Peas 31 25
Total
400
Phenotype
(O – E)2 E
(O – E)2 / E
Round Yellow Peas 36
225
0.16
Round Green Peas 75
0.48
Wrinkled Yellow Peas
Wrinkled Green Peas 25
1.44
Total
2.56

27. Do we accept or reject the null hypothesis?
Chi square = 2.56
Degrees of freedom = # of groups -1 = 4-1 = 3
P = .05
Critical value = 7.81
The chi-square values is less than the critical value so we ACCEPT the null hypothesis. There is no statistical difference between what we expected in the dihybrid cross and the observed result.