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Biological Concepts and Structures
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Biological Concepts and Structures
Biological Concepts and Structures MCQ
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1
Question
What are the carbohydrates that have the same chemical formula C6H12O6 but different structural formulas?
Answer
Glucose, galactose, and fructose.
2
Question
Which statement is most likely true about glucose, galactose, and fructose?
Answer
C. The carbohydrates have different properties because they have different arrangements of carbon, hydrogen, and oxygen atoms.
3
Question
What is the significance of compounds having the same chemical formula but different structural formulas?
Answer
They usually have different properties.
4
Question
What is formed when water and ammonia interact?
Answer
Hydrogen bonds.
5
Question
Which statement explains the formation of the hydrogen bond between water and ammonia?
Answer
B. The nitrogen has a partial negative charge, and the hydrogen attached to the oxygen has a partial positive charge.
6
Question
What causes the unequal sharing of electrons in water and ammonia?
Answer
The greater electronegativity of oxygen and nitrogen compared with hydrogen.
7
Question
How do the properties of water enable an insect to walk on its surface?
Answer
D. Hydrogen bonds between molecules at the surface of the water provide surface tension.
8
Question
What do hydrogen bonds in water produce that allows organisms to walk on the surface?
Answer
Surface tension.
9
Question
How do rabbits obtain carbon necessary for building biological molecules?
Answer
B. Rabbits eat plants and break down plant molecules to obtain carbon and other atoms.
10
Question
What happens to the molecules released by fish in an aquarium?
Answer
D. The ammonia molecules released by the fish are converted by the bacteria to nitrates.
11
Question
What did students observe in their controlled experiment investigating nutrients for plants?
Answer
The seedlings in the first group (potting soil) thrived better than those in the second group (sawdust).
12
Question
What monomers are produced when seedlings cannot access sufficient nutrients?
Answer
Amino acids and nucleotides.
13
Question
What describes the formation of a covalent peptide bond?
Answer
D. The formation of a covalent peptide bond in a dehydration synthesis reaction.
14
Question
What happens to a polypeptide chain during hydrolysis?
Answer
D. It represents a polypeptide chain that is broken down through a hydrolysis reaction.
15
Question
Which fatty acid is likely to be solid at room temperature?
Answer
C. Palmitic acid, because the absence of carbon-carbon double bonds allows the molecules to pack closely together.
16
Question
How do carbohydrates occur structurally?
Answer
B. They occur as monomers, chains of monomers, and branched structures.
17
Question
How do amino acids affect the tertiary structure of a protein?
Answer
B. The interactions of the different R-groups with other R-groups and with their environment determine the tertiary structure of the protein.
18
Question
What effect does a deletion of phenylalanine in CFTR protein have?
Answer
D. It will affect the primary, secondary, and tertiary structures of the CFTR protein.
19
Question
What role do cysteine amino acids play in protein stability?
Answer
B. The change leads to increased protein stability because of an increased number of S-S bonds in the tertiary structure of the proteins.
20
Question
What is the impact of R-groups on protein structure in water?
Answer
The hydrophilic R-groups are attracted to water, while hydrophobic R-groups are repelled.
21
Question
What describes a structural difference between DNA and RNA?
Answer
B. The backbone of DNA contains deoxyribose, whereas the backbone of RNA contains ribose.
22
Question
What is a nucleic acid fragment made up of?
Answer
A nucleic acid fragment is made up of four nucleotides linked together in a chain.
23
Question
What characteristic of RNA differentiates it from DNA?
Answer
RNA contains uracil, whereas DNA contains thymine.
24
Question
Which conclusion can be drawn from the representations of nucleic acid 1 and nucleic acid 2?
Answer
Nucleic acid 1 contains adenine-thymine base pairs, whereas nucleic acid 2 shows only uracil in the nucleotide chain and does not show any base pairing.
25
Question
Why do hydrogen bonds form between water molecules?
Answer
The slightly negatively charged O atom in one water molecule is attracted to one of the slightly positively charged H atoms in another water molecule, forming a weak hydrogen bond.
26
Question
What happens to water molecules as ice forms?
Answer
As water cools, the water molecules slow down, and the hydrogen bonds between them become more stable, causing them to space out in a crystalline form.
27
Question
How does ice floating on water benefit organisms?
Answer
Floating ice reduces heat loss from the water below, resulting in warmer water that is less likely to freeze to the bottom.
28
Question
What are the monomers that compose the enzyme bromelain?
Answer
Amino acids are the monomers of which bromelain is composed.
29
Question
How does bromelain work to prevent browning in fruits?
Answer
Bromelain acts by enabling the hydrolysis of the protein-polypeptide-amino acid chain, breaking apart the peptide bonds holding the amino acids together.
30
Question
What effect does a pH of 11 have on the activity of bromelain?
Answer
The activity of bromelain will decrease at a pH of 11.