护理入学考试生物练习卷（附答案）

What is a chromosomal deletion?

1. AThe swap of a single DNA base
2. BThe loss of a piece of a chromosome
3. CAn extra copy of a whole chromosome
4. DA piece of chromosome that is turned around

典型的人体体细胞中有多少条染色体？

1. A46
2. B23
3. C92
4. D44

Which bonds hold the two strands of a DNA double helix together?

1. AHydrogen bonds between the bases
2. BIonic bonds between the phosphates
3. CDisulfide bonds between the bases
4. DPeptide bonds between the sugars

In evolution, what does an organism's fitness mean?

1. AHow large the organism grows
2. BHow strong and fast the organism is compared with others
3. CHow many offspring it leaves that survive and reproduce
4. DHow long the organism lives

What causes cohesion between water molecules?

1. ACovalent bonds between neighbouring molecules
2. BHydrogen bonds between neighbouring molecules
3. CMagnetic forces between hydrogen atoms
4. DIonic bonds between oxygen atoms

How can bacteria pass antibiotic-resistance genes directly to other bacteria?

1. ABy conjugation, transferring plasmids through a pilus
2. BBy osmosis, moving genes in water
3. CBy mitosis, sharing copies of their chromosomes with neighbours
4. DBy meiosis, forming gametes with new alleles

A new infectious agent passes through filters that trap bacteria, does not grow on nutrient agar and multiplies only inside living cells. What is it most likely to be?

1. AA protozoan
2. BA bacterium
3. CA fungus
4. DA virus

Which parent's gamete decides the biological sex of a human baby, and why?

1. AThe mother's, because she gives two X chromosomes
2. BThe mother's, because an egg carries either an X or a Y
3. CBoth equally, because each gives one Y chromosome
4. DThe father's, because a sperm carries either an X or a Y