Exam 3 Flashcards
Shortly after ingesting a big plate of carbohydrate-rich pasta, you measure your blood’s hormone levels. What results would you expect, compared to before the meal?
Insulin after, GLucagon before
Why are proteolytic enzymes such as pepsin and trypsin secreted in an inactive form?
So they don’t digest the body
What do the secretions of the parietal cells of the stomach do?
Initiate the chemical digestion of protein in the stomach
Mutations in what genes lead to transformations in the idenitity of entire body parts?
Homeotic Genes
What makes each insect body segment different from another?
Different genes are expressed
What does the bicoid mutant tell us about the fucntion of bicoid gene in embyogenes
Anterior head formation
What happens during induction?
Cells move to new positions as an embryo establishes its three germ tissue layer
Meristematic tissue cells= what in humans?
Embryonic stem cells
An enzyme-linked receptor has been activated by a hormone. What is the likely downstream signaling event that transduces the signal?
Activation of a protein phosphorylation cascade
Where in the cell would you expect to find the receptors: first for estrogen (a steroid) and second for epidermal growth factor (a protein)?
Inside the cell, cell surface
What process uses intracellular oxygen?
Respiration
If the difference in partial pressure of gas on either side of the barrier to diffusion is 0, which of these events will occur?
No diffusion will occur because there is no gradient (High P to low P)
How do you calculate the Partial pressure of a gas?
Concentration in area x pressure(mmHg)
What does hemoglobin binding of oxygen include?
Cooperative binding,
Reversibility
Fe++
Ambient partial pressure of oxygen must be low
What is special about fetal Hemoglobin?
it has a higher affinity of Oxygen so moms blood doesn’t gank any of it.
What do Regulatory cascades do?
Establish body plans by a cascade of gene expression.
Genetic Regulatory cascade, describe the 6 steps of gene expression,
1.Morphogen from undifferentiated cells(anterior-posterior axes/ large body areas)
2.Gap Genes- Organize cells into segments for large body regions
3.Pair-Rule gene- Individual Segments
4. Segment-Polarity genes ; specificy regions in each individual segment
5. Hox Genes: Specify Structure, identity
6Effector genes finally deal with prolferation, death, movement, and interaction
characteristics of the lac operon
- involved in regulating metabolism of lactose specifically… operating beta galactosidase at lacZ and lactose permease at lacY (transports lactose into cell)
Beta-galactocidase
-cleaves lactose into glucose and galactose , expressed by lacZ
ara operon
Positive and negative control from an activator protein, arabinose,
lac operator
immediately downstream of lac operon promoter
Is the lac operon under positive or negative control and what involvement does the lacl gene have?
Negative control, it is actively turned off in the absence of lactose.
lacl is a repressor that when transcripted keeps lac operon from being acrivated, it is the negative controller
How does the lacl negative controller get relieved ?
when lactose is present it binds to the repressor protein encodedby lacl and causes a conformational change that releases the repressor protein from the operator site.
Arabinose present
Activator protein arabinose causes Transcription of ara operon , positive regulation of the ARA operon
