Biology Practice Questions

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cl24uw06

cl24uw06

cl24uw06
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I thought it would be helpful to start a link with biology practice questions. Here is the first one:

Which RNA typically contains the fewest nucleotides?
A. rRNA
B. tRNA
C. mRNA
D. All types of RNA contain the same number of nucleotides
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Which step in translation does NOT consume a high-energy phosphate bond?
A. Aminoacyl-tRNA (initiator tRNA) binding to the ribosome
B. Peptidyl-transferase reaction
C. Amion acid activation
D. Translocation
 
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cl24uw06 said:
I thought it would be helpful to start a link with biology practice questions. Here is the first one:

Which RNA typically contains the fewest nucleotides?
A. rRNA
B. tRNA
C. mRNA
D. All types of RNA contain the same number of nucleotides
Click to expand...

Answer: B
The tRNA molecules contain about 75-90 nucleotides, whereas common rRNA's and mRNA's often contain 1000-3000 nucleotides. The rRNA's are fairly large because they make up the structure of ribosomes (along with protein). The mRNA's have many nucleotides because they code for proteins
 
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cl24uw06 said:
Which step in translation does NOT consume a high-energy phosphate bond?
A. Aminoacyl-tRNA (initiator tRNA) binding to the ribosome
B. Peptidyl-transferase reaction
C. Amion acid activation
D. Translocation
Click to expand...

Answer: B
Only the peptidyl-transferase reaction does not require energy. The aminoacyl-tRNA binding to ribosome involves initiation factors and energy (GTP). Amino acid activation requires energy (the cleavage of ATP to AMP and PPi). Translocation requires an elongation factor and energy (GTP).
 
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cl24uw06 said:
The backbone of a single strand of RNA consists of alternating:
A. sugars and hydrogens.
B. hydrogens and nitrogenous bases
C. nitrogenous bases and sugars
D. none of the above
Click to expand...

is it D...should it be sugars and phosphates?
 
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cl24uw06 said:
The backbone of a single strand of RNA consists of alternating:
A. sugars and hydrogens.
B. hydrogens and nitrogenous bases
C. nitrogenous bases and sugars
D. none of the above
Click to expand...

Answer: D
RNA consists of a sugar-phosphate backbone, with the nitrogenous bases guanine, cytosine, uracil, and adenine progecting from the backbone.
 
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cl24uw06 said:
From which molecule could a cell extract the greatest amount of energy through the normal pathways of aerobic respiration?
A. FADH2
B. ATP
C. NADH
D. Pyruvic acid
Click to expand...

Is the Answer B? Where are you getting these questions.
 
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cl24uw06 said:
From which molecule could a cell extract the greatest amount of energy through the normal pathways of aerobic respiration?
A. FADH2
B. ATP
C. NADH
D. Pyruvic acid
Click to expand...

Answer: D
Pyruvic acid enter the TCA cycle and leads to the generation of both NADH and FADH2 molecules. Both then enter the oxidative phosphorylation pathway and generate many ATP. A single NADH molecule leads to the preduction of anly 3 ATP. A single FADH2 molecule leads to the production of only 2 ATP.
 
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Oxidation of molecules is essential for releasing energy in a form that can be used by cells. All cellular oxidations have in common:
A. addition of oxygen
B. removal of water
C. removal of hydrogen
D. removal of electrons
 
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Which statement BEST explains why the genetic code is considered degenerate?
A. One codon can code for several amino acids
B. Codons code for amino acids
C. Amino acids may form a large variety of possible proteins
D. Most amino acids have several codons
 
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One molecule of acetyl CoA, radioactively labeled at each carbon atom, enters the Krebs cycle. After one turn of the cycle, how many molecules of radioactive CO2 are produced?
A. 0
B. 1
C. 2
D. 3
 
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Enzyme cofactors are BEST described as:

A. nonprotein substances required for enzyme activity
B. small, nonprotein, organic molecules
C. metal ions or coenzymes that bind tightly to an enzyme
D. catalysts
 
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If anyone would like the answers and explanations to any of these questions please let me know. Also if anyone else has access to some good biology questions post them here so we can get a great study resource compiled.
 
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ok here are my answers:
A) addition of oxygen
-----------------
D) after 4 generations 1/16 or 6.25%
--------------
D) nuceic acid
-----------
D) size of mitochondria
--------------
B) C-U-A
--------------
D) MOst amino acids have severak codons
------------------
2 CO2 molecules
------------------
A)phosphodiester
---------------------
A)non-protein substance required for enzyme acitivity
--------------------
A)gylcolysis seems to be the best answer because it's 1st in the chain of reactions
----------------------------
D) I think phosphofructokinase because it's the enzyme for the irreversible state.
 
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cl24uw06 said:
Oxidation of molecules is essential for releasing energy in a form that can be used by cells. All cellular oxidations have in common:
A. addition of oxygen
B. removal of water
C. removal of hydrogen
D. removal of electrons
Click to expand...

Answer: D

Cellular oxidation refer to the removal of electrons
 
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cl24uw06 said:
Cells are grown in N15 for many generations and transferred to N14 media. After how many generation does the cellular DNA contain 6.25% N15.

A. One
B. Two
C. Three
D. Four
Click to expand...

Answer: D

Solving this problem requires understanding semiconservative replication of DNA. After one generation, only half of the DNA is N15 labeled. After a second generation, one fourth of the DNA is N15. By generation four, only one sixteenth of the DNA is N15; that is, approximately 6.25%
 
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cl24uw06 said:
ATP is a chemical compound classified as a:
A. nucleoside
B. nucleotide
C. nucleic acid
D. deoxyriboside
Click to expand...

Answer: B

ATP (adenosine triphosphate) is a nucleotide. Nucleotides include the nitrogenous base, sugar, and phosphate residue. Nucleosides (e.g., adenosine) include only the base and sugar residue.
 
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cl24uw06 said:
Escherichia coli is a common intestinal becterium. One would expect a typical E. coli cell to be about the size of a(an).
A. human liver cell
B. polyribosome
C. amoeba
D. mitochondria
Click to expand...

Answer: D

A bacterial cell is about the size of a mitochondrion. In one popular theory, scientists have postulated that the mitochondria have evolved from bacteria because of the similarities between bacterial and mitochondrial DNA.
 
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cl24uw06 said:
If a portion of a DNA base sequence is G-A-T, the anticodon sequence complementary to the mRNA of this DNA sequence is:
A. G-A-T
B. C-U-A
C. G-A-U
D. G-U-A
Click to expand...

Answer: C

If the DNA sequence is G-A-T, the mRNA sequence is C-U-A, and the anticodon sequence complementary to the mRNA is G-A-U.
 
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cl24uw06 said:
Which statement BEST explains why the genetic code is considered degenerate?
A. One codon can code for several amino acids
B. Codons code for amino acids
C. Amino acids may form a large variety of possible proteins
D. Most amino acids have several codons
Click to expand...

Answer: D

The genetic code is considered degenerate because several different codons may code for a single amino acid
 
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cl24uw06 said:
One molecule of acetyl CoA, radioactively labeled at each carbon atom, enters the Krebs cycle. After one turn of the cycle, how many molecules of radioactive CO2 are produced?
A. 0
B. 1
C. 2
D. 3
Click to expand...

Answer: A

In this difficult question, the two labeled carbons of acetyl CoA add to the four carbons of oxaloacetate to give the six-carbon compound, citrate. The two CO2 molecules that are lost in one turn of the Krebs cycle are not the two carbon units just added by acetyl CoA. They are the carbons that were part of oxaloacetate. However, in the subsequent turns of the Krebs cycle, these radioactive carbons are lost.
 
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cl24uw06 said:
Which bond links nucleotides to one another in RNA?
A. Phosphodiester bonds
B. Glycosidic bonds
C. Phosphate bonds
D. Hydrogen bonds
Click to expand...

Answer: A

A glycosidic bond links a base to a pentose sugar. A phosphate ester links a nucleoside to phosphoric acid. Hydrogen bonds bridge two DNA strands.
 
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cl24uw06 said:
Enzyme cofactors are BEST described as:

A. nonprotein substances required for enzyme activity
B. small, nonprotein, organic molecules
C. metal ions or coenzymes that bind tightly to an enzyme
D. catalysts
Click to expand...

Answer: A

Cofactors are nonprotein substances required for the activity of some enzymes. They include metal ions and coenzymes. Choice B describes coenzymes. Choice C describes prosthetic groups.
 
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cl24uw06 said:
The process of respiration does NOT include:

A. glycolysis
B. generation of acetyl CoA from pyruvate
C. the Krebs cycle
D. oxidative phosphorylation
Click to expand...

Answer: A

Respiration refers to the metabolism of glycolysis products that are broken down to CO2 and H2O, using oxygen as a final electron acceptor. Therefore, the process of glycolysis is not included in respiration. The generation of acetyl CoA from pyrovate, the Krebs cycle, and the process of oxidative phosphorylation are all includid in respiration.
 
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cl24uw06 said:
Which enzyme catalyzes the rate-limiting step in glycolysis?

A. Hexokinase
B. Pyruvate kinase
C. Enolase
D. Phosphofructokinase
Click to expand...

Answer: D

Phosphofructokinase irreversibly phosphorylates fructose-6-phosphate to fructose-1,6-diphosphate. It catalyzes the major rate-limiting step in glycolysis. This enzyme is also the key controlling step of glycolysis. ATP acts as a negative allosteric modulator, whereas ADP acts as a positive allosteric modulator of phosphofructokinase. By this mechanism, the ultimate high-energy product of glycolysis and respiration, ATP, can control the activity of glycolysis.
 
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Bioenergetically, for each mole of acetate that it oxidizes, the Krebs cycle produces:

A. 12 ATP
B. 2 moles NADH, 2 moles FADH2
C. 3 moles NADH, 1 mole FADH2, 1 mole GTP
D. 2 moles NADH, 3 moles FADH2
 
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Lactic acid is generated as an end product of anaerobic metabolism. The gland or organ that removes lactate from the circulation and resynthesizes it to acetyl CoA is the:

A. liver
B. spleen
C. kidney
D. pituitary
 
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Lactic acid is generated as an end product of anaerobic metabolism. The gland or organ that removes lactate from the circulation and resynthesizes it to acetyl CoA is the:

A. liver
 
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Skin infections are most commonly caused by spherically shaped bacteria found in clusters. The most likely name for these bacteris is:

D. staphylococci[/QUOTE]

staph = clusters; cocci = round shape
 
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cl24uw06 said:
Bioenergetically, for each mole of acetate that it oxidizes, the Krebs cycle produces:

A. 12 ATP
B. 2 moles NADH, 2 moles FADH2
C. 3 moles NADH, 1 mole FADH2, 1 mole GTP
D. 2 moles NADH, 3 moles FADH2
Click to expand...

Answer: C

The Krebs cycle produces 6 NADH, 2 FADH2, and 2 GTP moleucles per glucose molecule metabolized. The question askes for the bioenergetics per mole of acetate, which would would be half the total production per glucose molecule.
 
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The production of ATP from the energy stored in NADH depends on:

B. oxidation/reduction

cytochrome etc. gets oxidized & reduced by cytochrome reductase & cytochrome oxidase etc etc etc.
 
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cl24uw06 said:
Lactic acid is generated as an end product of anaerobic metabolism. The gland or organ that removes lactate from the circulation and resynthesizes it to acetyl CoA is the:

A. liver
B. spleen
C. kidney
D. pituitary
Click to expand...

Answer: A

The liver removes lactate from the circulation and metabolizes it to acetyl CoA, which is returned to the circulation, in a process known as the Cori cycle. The spleen is mainly involved in stroage of old red blood cells. The kidney produces concentrated urine and reabsorbs and excretes solutes. The pirtitary produces and releases horomones.
 
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cl24uw06 said:
What is the ultimate fate of the glucose carbon chain in metabolism?

A. ATP
B. CO2
C. O2
D. NADH
Click to expand...

Answer: B

Glucose is metabolized to pyruvate in glycolysis. Pyruvate loses one CO2 to form acetyl CoA. Each acetyl CoA enters the Krebs cycle where it is decarboxylated. There fore, the ultimate fate of glucose carbon units is CO2
 
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Are all these questions from the "High Yield Biology" book???????
 
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