Exam 2 Flashcards
What is the framework of the membrane structure?
Phospholipid bilayer
What kind of molecules do phospholipids contain?
Amphipathic molecules
What components do the membrane structure contain?
Proteins and carbohydrates
What are the three types of proteins bound to membranes?
Transmembrane proteins, lipid anchored proteins, and peripheral membrane proteins
What do the transmembrane proteins do?
have one or more regions physically embedded in the phospholipid bilayer
What do lipid-anchored proteins do?
lipid-molecule is COVALENTLY attached to an amino acid side chain within the protein; lipid tails are inserted into the membrane
what do peripheral membrane proteins do?
NON COVALENTLY bound either to integral membrane proteins that project out from the membrane, or to polar head groups of phospholipids
What percentage of genes encode transmembrane proteins?
20-30%
How are computer programs used for transmembrane proteins?
predict the number of transmembrane proteins in an organism based on DNA sequence data of an organisms genome
What is cystic fibrosis?
A lung disease caused by a problem with transmembrane proteins in membranes
What is fluidity?
Individual molecules remain in close association but can readily move within a membrane
Molecules capable of enzymatic activity include
A. RNA and DNA
B. Proteins only
C. RNA and proteins
D. DNA and proteins
E. RNA only
C. RNA and proteins
In a biochemical pathway, the product released by the first enzyme becomes the substrate for the second enzyme.
True or False
True
Inhibiting one step in a biochemical pathway will not have any affect on the rates of the other reactions in the pathway.
True or False
False
Where is sucrase found in the human body?
A) on the gastric surface
B) in the pancreas
C) in the liver
D) on the microvilli of the small intestine
D. On the microvilli of the small intestine
Sucrose uses ____ to cleave sucrose into two monosaccharides
A. Oxygen
B. Carbon dioxide
C. Water
D. Glucose
E. Fructose
C. Water
What happens to sucrase when it binds to sucrose?
A. Sucrase goes through a conformational change
B. Sucrase becomes denatured
C. Sucrase is cleaved in half
D. Sucrase releases energy to the sucrose
A. Sucrase goes through a conformational change
How often can a Sucrase molecule be used to hydrolyze sucrose?
A. Once
B. Twice
C. Many times
D. Never
C. Many times
Most enzymes are
A. Carbohydrates
B. Polysaccharides
C. Lipids
D. Steroids
E. Proteins
E. Proteins
Which of the following binds most tightly to the active site of an enzyme?
A. None of these choices are correct
B. Substrate
C. Product
D. Water
E. Any other enzyme
B. Substrate
An enzyme catalyzes a chemical reaction in the cell, but can only be used once.
True or False
False
An enzyme may catalyze a reaction by stressing or destabilizing the bonds of the substrates. This critical point in the enzymatic reaction is known as the
A) activation energy
B) change in free energy
C) energy state
D) transition state
E) enzyme-substrate complex
D. Transition state
Cells obtain energy by _________ food molecules such as glucose.
A) reducing
B) phosphorylating
C) anabolizing
D) redoxing
E) oxidizing
E. Oxidizing
What happens when the coenzyme NAD+NAD+ gains an H atom?
A. It also gains an electron causing it to be oxidized
B. It loses energy
C. It also gains an electron causing it to be reduced
D. It also gain a proton causing it to be reduced
E. It also gains a proton causing it to be oxidized
C. It also gains an electron causing it to be reduced