Flashcards in Red Exam 3 Deck (39):
Sunlight absorbed by chlorophyll is used to energize electrons, which are passed from high energy electron acceptors, thought the electron transport system, and is eventually used to reduce NADPH. From what molecules were the electrons obtained
Both chloroplasts and mitochondria use chemiosmosis to phosphorylate ADP. Where are the ATP synthase located in chloroplasts
photosynthesis is a process that captures light energy and converts it into chemical energy that can be used to make sugars. What happens when a plant cell is placed in the dark?
the plant metabolize glucose using glycolysis and oxidative phosphorylation
RUBISCO is an important enzyme in chloroplasts. What does RRUBISCO do?
it is a calvin cycle enzyme that captures carbon dioxide and fixed it on ribulose bis phosphate
most of the ATP produced in chloroplasts during photosynthesis is used
to assemble sugar
bacteria that associate with Hawaiian bobtail squid can produce light but inly under certain conditions. What are the conditions?
bacteria must grow to a certain concentration that promotes their signaling to each other to put out light
GLUT4 is a channel in muscle and liver cells that can allow facilitated diffusion of glucose across the plasma membrane. GLUT4 normally is located in the membranes of secretory vesicles int eh cytoplasm. The display of GLUT4 is stimulated when the cells are exposed to insulin. What would you predict would happen if GLUT4 proteins lacked ER signal sequence?
The cell would be unable to take up glucose even if insulin is present
what do protein kinases do in a cell
protein kinases add phosphate groups to proteins
How is cyclic AMP produced in a cell
when activated adenylyl cyclades produce cAMP from ATP
protein phophatases are a family of enzymes that specifically remove phosphate groups from proteins that were added by protein kinases. Vandate is an inhibitor of phosphatases in eukaryotic cells. What effect would vanadate have on the response of cells to signal received by receptor kinases?
the response of the cell would last longer than it normally would
How does a G-protein become inactivated?
G-proteins hydrolyze the GTP to form DDP and release phosphate. The G-proteins with GDP bound can no longer bind and activate the downstream molecule
where would you expect to find a receptor for a protein hormone like insulin?
on the plasma membrane
Caffeine is an inhibitor of phosphodiesterase. Therefore, the cell of a person who has recently consumed coffee weill have increased levels of
Cholera is caused by a toxin that prevent s GTP hydrolysis by G-proteins. How can this cause diarrhea
Cholera toxin prevents GTP hydrolysis by a G protein that activates adenylyl cyclase, cAMP continues to be produces, which activates a protein kinase that activates a CFTR channel, which allows CL- to diffuse into the intestine. Water follows osmosis
Where are CL- channels associated with cholera located in a cell
on the plasma membrane that faces the lumen of the intestine
Photoreceptors in a human retina don't divide after they have differentiated. In what stage of the cell cycle are rod cells in your eye?
There are about 6 billion nucleotide base pairs in a human cell but only 1.5% of those nucleotides are expressed. What is meant by gene expression
genes that are transcribed by RNA polymerase to make mRNA that is translated to assemble proteins
During which stage of cell division do sister chromatids separate?
meiosis 2 and mitosis
Soppose you observe a mouse cell with 40 chromosomes during metaphase of mitosis. If you stain the DNA molecules with a fluorescent stain, how many DNA molecules would you expect to find in this mitotic mouse cell
Consider a dog intestinal cell with 78 chromosomes. As the cell goes through mitosis to produce more intestinal cells, how many centromeres would you expect to be present?
What might tell an individual human cell that it should divide
growth factors that bind cellular receptor molecules
Ras is a G-protein that when mutated is associated with causing cancer. What is a function of a non cancer causing Das protein
replaying a signal from a growth factor receptor
SNA polymerase is an enzyme that is responsible for replicating DNA. During which stage in the cell cycle would you expect to find DNA polymerase being most active
Cyclins activate cyclin-dependent protein kinases that phosphorylate other proteins important for the progression of the cell cycle. Why don't cyclins continuously stimulate cell division
Cyclins are only synthesized at or just prior to the time that they are needed in the cell cycle an d are degrading after the cell completes that portion of the cell cycle
Which of the following is not true regarding the protein CDK
the levels of CDK change with the cell cycle
Suppose a cell has a gene that codes for a tumor suppressor X. What would happen to a diploid celll if one of the allies for that gene was mutated and could not produce the tumor suppressor protein
the cell would not be affected
location of the lowest pH in the light
in the lumen of a thylakoid membrane
ATP synthase enzymes
on the surface of a thylakoid membrane
RUBISCO and CO2 fixation
in the stroma
Where in a plant cell would you expect to find ATPsynthase molecules
thylakoid membran and on the cristae of the plant mitochondria
Defects in a cystic fibrosis chloride ion channel are associated with cystic fibrosis, daises in which patients have which mucus that cannot be transported out of the lungs. What kind of transmembrane protein is a CFTR
Ligand-gated ion channel
Colon cancer are caused by defects in proteins produced by specific genes. Is it reasonable to state that there is one gene that is responsible for any particular cancer?
1) loss of tumor suppressor genes
2) actuation of res oncogene
3) loss of two more tumor suppressor genes
4) additional mutations
Suppose you have a patient whose pancreas secretes plenty of insulin in response to sugar levels in the bloodstream but you also find the patient has high glucose levels in their bloodstream. Propose a hypothesis to explain why the insulin is not stimulating sugar uptake
insulin receptor on cells that take up glucose may not be displayed, synthesized, or might be mutated and bind insulin
How is a G-protein activated?
G=protein coupled receptor removes the GDP from an inactive F protein and replaces it with GTP
How is a G-protein inactivates?
GTP is hydrolyzed and leaved only GDP bound to the G-protein
What happens to the adenylyl cyclase if the G-protein cannot be inactivated?
adenylyl cyclase that is activated by a GTP-G protein will continue to produce cyclin AMP from ATP
How can this cause the diarrhea associated with cholera
Continued production of cAMP will continue to activate protein kinase A. The protein kinase A will continue to phosphorylate the CFTR channel and cells will continue to release chloride ions into the intestine. The increased concentration of chloride ions will draw water from cells and tissue spaces and fill the intestinal lumen with water. The increased water will produce diarrhea, tissues will dehydrate, and an infected persona may die
what is the best and least expensive way to treat cholera patients and prevent cholera from reading in a community
provide a good sewage/waste treatment to prevent spread of cholera-producing bacteria and provide clean, bacteria free water for drinking washing and cooking to prevent infection instate first place