Question

1. a mutation occurs in the dna sequence of a cell. which of the following could be a possible consequence?

a) the cell may produce a malfunctioning protein
b) the cell may function normally
c) the cell will always die immediately
d) the cell will become a virus

1. a patient has damage to their alveoli in the lungs. predict how this might affect their body systems.

a) it would improve oxygen absorption
b) it would have no effect
c) it would increase hormone production
d) it would decrease the efficiency of gas exchange, affecting oxygen delivery to tissues

1. refer to the dna base pairing chart below: | base in dna strand 1 | base in dna strand 2 | | adenine (a) | thymine (t) | | thymine (t) | adenine (a) | | cytosine (c) | guanine (g) | | guanine (g) | cytosine (c) | given a dna sequence, how would you use the chart to identify the complementary base pairs?

a) by matching all bases randomly
b) by matching adenine with guanine and cytosine with thymine
c) by matching thymine with guanine and adenine with cytosine
d) by matching adenine with thymine and guanine with cytosine

1. a scientist observes a cell with a cell wall, chloroplasts, and a large central vacuole. what type of cell is this, and what is its likely function?

a) bacterial cell; infection
b) fungal cell; decomposition
c) animal cell; movement
d) plant cell; photosynthesis

1. if a mutation caused a change in the sequence of bases in a gene, how could this affect the protein produced?

a) the protein would become dna
b) the protein would not be affected
c) the protein could have a different shape and function
d) the protein would always be longer

1. a person is experiencing muscle weakness and fatigue. which two body systems might be involved, and how could their interaction explain the symptoms?

a) muscular and nervous; nerve signals may not be properly stimulating muscles
b) circulatory and respiratory; increased oxygen delivery
c) endocrine and skeletal; hormone imbalance strengthens bones
d) digestive and immune; poor digestion causes infection

Explanation:

25.

• a) A mutation can lead to a malfunctioning protein as it changes the genetic code which is used to synthesize proteins.
• b) Sometimes, due to the redundancy of the genetic code (multiple codons can code for the same amino acid), a mutation may not change the amino - acid sequence, so the cell may function normally.
• c) Cells do not always die immediately when a mutation occurs. There are repair mechanisms, and some mutations are silent.
• d) A cell cannot become a virus. Viruses are non - cellular entities with their own genetic material and protein coats.

26.

• a) Damage to alveoli would not improve oxygen absorption. Alveoli are the sites of gas exchange.
• b) Damage to alveoli will have an effect as they are crucial for gas exchange.
• c) Alveoli are not related to hormone production.
• d) Alveoli are responsible for gas exchange (oxygen in, carbon dioxide out). Damage to them decreases the efficiency of gas exchange, which affects oxygen delivery to tissues.

27.

• a) Bases in DNA pair specifically (A - T, G - C), not randomly.
• b) Adenine pairs with thymine, not guanine; cytosine pairs with guanine, not thymine.
• c) Thymine pairs with adenine, and cytosine pairs with guanine.
• d) Adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C) in DNA base - pairing.

28.

• a) Bacterial cells do not have chloroplasts.
• b) Fungal cells do not have chloroplasts.
• c) Animal cells do not have cell walls, chloroplasts, or large central vacuoles.
• d) Plant cells have cell walls, chloroplasts (for photosynthesis), and large central vacuoles.

29.

• a) A protein cannot become DNA. Proteins and DNA are different macromolecules with different structures and functions.
• b) A mutation in a gene (which codes for a protein) can affect the protein. Only in the case of silent mutations (due to genetic code redundancy) there is no effect. But it's not always the case.
• c) A change in the base sequence of a gene (mutation) can lead to a different amino - acid sequence in the protein. A different amino - acid sequence can result in a different shape (due to changes in folding) and function of the protein.
• d) A mutation does not always make the protein longer. It can delete bases (making it shorter) or substitute bases (no change in length in some cases).

30.

• a) The muscular system needs signals from the nervous system to contract. If nerve signals (from the nervous system) do not properly stimulate muscles (muscular system), muscle weakness and fatigue can occur.
• b) Increased oxygen delivery would not cause muscle weakness. Also, damage to alveoli (as in respiratory system) would decrease oxygen delivery.
• c) Hormone imbalance in the endocrine system affecting the skeletal system (bones) is not directly related to muscle weakness.
• d) Poor digestion (digestive system) causing infection (immune system) is not the direct cause of muscle weakness and fatigue.

Answer:

1. A. The cell may produce a malfunctioning protein; B. The cell may function normally
2. D. It would decrease the efficiency of gas exchange, affecting oxygen delivery to tissues
3. D. By matching adenine with thymine and guanine with cytosine
4. D. Plant cell; photosynthesis
5. C. The protein could have a different shape and function
6. A. Muscular and nervous; nerve signals may not be properly stimulating muscles