BMB 211 exam 4

Where do the enzymatic reactions of the Calvin cycle take place?

stroma of the chloroplast

What is the primary function of the Calvin cycle?

synthesize simple sugars from carbon dioxide

The reactions that produce molecular oxygen (O₂) take place in

the thylakoid membrane of the chloroplast

Which of the events listed below occurs in the light reactions of photosynthesis?

ATP is phosphorylated to yield ADP.

NADPH is reduced to NADP⁺.

 Light is absorbed and funneled to reaction-center chlorophyll a.

NADP is produced.

 Carbon dioxide is incorporated into PGA.

Light is absorbed and funneled to reaction-center chlorophyll a.

What does photosystem 1 do?

it receives electrons from the thylakoid membrane electron transport chain

Name the two products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

ATP and NADPH

Name the main product of the dark reactions of photosynthesis that are utilized in the Calvin cycle?

G3P

Water passes quickly through cell membranes because

it moves through aquaporins in the membrane

What kinds of molecules pass through a cell membrane most easily? (2 things)

Small and hydrophobic

What would make for a more fluid membrane?

more unsaturated phospholipids

What is a characteristic feature of a carrier protein in a plasma membrane, what does it allow?

It exhibits a specificity for a particular type of molecule

Unsaturated fats have what that helps them remain fluid at room temperature

double bonds in the fatty acid tails

Does Na⁺ ions moving out of a mammalian cell bathed in physiological saline require energy from ATP hydrolosis?

Yes

Diffusion is (active or passive) and moves from high to low…. or low to high

passive process which moves from high to low concentrations

Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?

CO₂

an amino acid

glucose

K⁺

starch

CO2

Where are peripheral proteins found in the lipid bilayer?

on the outer or inner surfaces

White blood cells engulf bacteria through what process?

endocytosis

Why are lipids and proteins free to move laterally in membranes?

There are only weak hydrophobic interactions in the interior of the membrane

Explain why the body needs to use energy to balance electrolytes (sodium/pottasium)

ATP is required to move sodium ions against their concentration gradient outside the cell

What will happen to the opening of the sodium-potassium pump if no ATP is present in a cell? (what will it remain facing, and which ions will be bound/unbound)

It will remain facing the cytoplasm, with sodium ions bound

The sodium-potassium pump is called an electrogenic pump because it

contributes to the membrane potential

The double bonds in naturally occurring fatty acids are usually _______ isomers

cis

Name four types of lipids

Fatty acids, steroids, waxes, triglycerides

Decomposers convert organic nitrogen to ________ (four)

ammonia, nitrate, nitrite, dinitrogen

The ammonia that is incorporated into urea molecules is NOT produced in reactions catalyzed by which enzyme

Serine hydroxymethyltransferase

Amino acids whose degradation yields α-ketoglutarate include which ones (three)

arganine, glutamine, histidine

Amino acids whose degradation yields succinyl-CoA includes all of the following except ________.

 

Methionine

Isoleucine

Valine

Histidine

None of the above is correct

Histidine

The end product of uracil degradation is ________.

Beta alanine

In general, catabolism of amino acids begins with

removal of the amino group

Urea is synthesized in which organ?

Liver

What are the seven metabolic products produced by the degradation of amino acids?

acetoacetyl-CoA

acetyl-CoA

oxaloacetate

fumarate 

succinyl-CoA

α-ketoglutarate

Ammonia

In humans the purine ring cannot be degraded. How is it excreted?

uric acid

The glutamate family of amino acids DOES NOT include

lysine

The bonds that link the base pairs in the DNA double helix are ________.

hydrogen bonds

Adenine is a purine.

true

A nucleotide consists of only a base and a sugar. (T/F)

false

A nucleotide consists of only a base and a sugar. (T/F)

true

is glucose composed of nucleic acids?

NO

Describes the eukaryotic chromosome, what is it composed of?

It consists of a linear molecule of double-stranded DNA plus proteins.

Why do histones bind tightly to DNA?

Histones are composed predominantly of positively charged amino acids , and DNA is negatively charged.

Name three differences btwn DNA and RNA

RNA has uracil, RNA is single stranded, RNA has ribose (not deoxyribose like DNA)

The DNA "backbone" is composed of (what kind of bond between what and where)

A phosphodiester bond between 3^! and 5^! hydroxyl groups of adjacent deoxyribose residues

Nucleosomes are NOT composed of which H?

H5

Protein synthesis, using the mRNA template is called _____. 

translation

In nucleosome structure the histone ________ aids in stabilizing the wrapping of DNA around the protein octomer.

H1

The melting point of a DNA molecule increases as the GC (guanine/cystine) content increases. (T/F)

true

a purine is composed of a (what ring(s))

6 member ring and a five member ring

pyrimidine is composed of a

6 member ring

Chargaff's rule apply to DNA but not RNA. (T/F)

true

The Z-form of DNA tends to occur where/when

alternating purine-pyrimidine sequences

Which is more likely to have a Z form DNA

GCGCGC

ATATATAT

GCGC

Topoisomerases are associated with

supercoiling of DNA

The T_m for melting the double helix is:

The midpoint of the range over which the helix denatures

The hydrogen bonding interactions in a Watson-Crick AT base-pair involve what units in the adenine base?

 

N-1 and the amino group on C-6

Why is the membrane considered 'semi-permeable' rather than 'permeable'? (what three things does it regulate on)

It regulates the passage based on size, charge and solubility

Describe the movement of molecules during facilitated diffusion? (what do molecules do and through what)

Molecules move down their gradient through a transport protein

If a cell is placed in a hypertonic solution, what will be the net movement of water? (what happens to the cell as a result)

water moves out of the cell causing it to shrivel

The release of neurotransmitters into a synapse is an example of what?

exocytosis

What happens to the surface area of the plasma membrane during heavy endocytosis?

It decreases as membrane sections are internalized via vesicle formation

How does the cell balance the change in surface area of plasma membrane due to endocytosis ?

Cells often use exocytosis to rapidly replenish the membrane surface, maintaining a dynamic equilibrium

In the Na+/K+ pump cycle, what is the primary role of ATP phosphorylation?

To induce conformational change that releases sodium ions to the extracellular space

Name this

3-phosphoglycerate

Name this

serine

Purines are 6-membered rings fused to a 5-membered ring. (T/F)

True

Name the three pyrimidines

Thymine, cytosine, uracil

Name the two purines

adenine, guanine

What is this?

Adenine

Name this

uracil

Describe the flow of genetic information as stated in the central dogma of molecular biology (three steps)

DNA to RNA to protein

There are approximately _________ human genes.

20,000

Name this

3-phosphoglycerate

What is the first product in photosynthesis

3-phosphoglycerate

Name this substrate

Ribulose-1,5-bisphosphate

Name the first susbtrate in photosynthesis

Ribulose-1,5-bisphosphate

For every three molecules of CO2 that enter the cycle, how many molecules of Glyceraldehyde-3-phosphate (G3P) actually exit to be used for sugar synthesis?

1

During the reduction phase, what molecules provided by the light reactions are used to convert 3-PGA into G3P? (2)

ATP and NADPH

Where is the oxygen produced during photosynthesis?

In the thylakoid

Where is the chlorophyll located in a plant?

Thylakoid membrane

What is the function of Rubisco?

carbon fixation

Atrazine is a chemical that blocks the electron from leaving photosystem II. What would be the immediate effect on the plant?

Prevents ATP synthesis

Lipids are the biomolecules of choice for storage of metabolic energy because they

yield a large amount of energy upon oxidation

Body fat is a major storage form of energy because it

aggregates in a highly anhydrous form (without additional water weight) meaning it is dense, holds a lot of energy in not a lot of space

is cholesterol in plant cell membranes?

No

When we say that biological membranes are asymmetric structures we mean that

lipids are not evenly distributed transversely in the membrane

What would be the most likely interaction between a peripheral membrane protein that contained a high lysine content and a membrane?

ionic interaction

Is H1 found on the nucleosome bead?

Nah

What does topoisomerase do functionally

relieves strain in the DNA ahead of the replication fork

In nucleosome structure the histone ________ aids in stabilizing the wrapping of DNA around the protein octomer.

H1

The NADPH required for the Calvin cycle comes from

photosystem 1

The light reactions of photosynthesis supply the Calvin cycle with

ATP and NADPH

The pH of the inner thylakoid space has been measured, as have the pH of the stroma of a particular plant cell. Which, if any, relationship would you expect to find?

The pH within the thylakoid is less than that of the stroma.

The reactions that produce molecular oxygen (O₂) take place in

the light reactions alone

Name the three molocules found in calvin cycle and glycolosis

1-3 bisphosphoglycerate, G3P, 3-phosphoglycerate

Oxygen released as a result of photosynthesis is a direct by-product of 

splitting water molecules.

Where are the molecules of the electron transport chain found in plant cells?

thylakoid membranes of chloroplasts

Where do the enzymatic reactions of the Calvin cycle take place?

stroma of the chloroplast

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

ATP and NADPH

Is oxygen released during the calvin cycle?

No

What does the chemiosmotic process in chloroplasts involve?

forming the proton gradient

Ribulose–1,5-bisphosphate carboxylase catalyzes the carboxylation of ribulose-1,5-bisphosphate to form

Two molecules of 3-phosphoglycerate