Биология для вступительных экзаменов на сестринские программы: лист заданий с ответами

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

1. AIonic bonds between the phosphates
2. BPeptide bonds between the sugars
3. CHydrogen bonds between the bases
4. DDisulfide bonds between the bases

Which enzyme unwinds the DNA double helix and separates the two strands for copying?

1. ALigase
2. BAmylase
3. CHelicase
4. DLipase

What is the main material in the cell wall of bacteria?

1. APeptidoglycan
2. BKeratin
3. CCellulose
4. DChitin

Почему грамположительные бактерии окрашиваются в фиолетовый цвет при окраске по Граму?

1. AИх тонкая стенка покрыта наружной мембраной, богатой липидами
2. BУ них вообще нет клеточной стенки
3. CИх толстая стенка из пептидогликана удерживает фиолетовый краситель
4. DОни содержат хлорофилл

Матричная цепь ДНК читается как T-A-C. Каков соответствующий кодон мРНК?

1. AU-T-G
2. BA-U-G
3. CT-A-C
4. DA-T-G

What is meant by independent assortment in meiosis?

1. AHomologous pairs line up randomly, so gametes get different mixes of chromosomes
2. BAll chromosomes from the mother go into the same gamete
3. CSister chromatids stay joined until the end of meiosis, so all gametes are identical
4. DDNA is copied separately in each chromosome

A patient is given a large volume of hypotonic IV fluid too quickly. What is the most likely effect on the patient's cells?

1. ASalt moves into the cells, and they burst
2. BNothing changes, because cells are not affected by IV fluid
3. CWater moves out of the cells, and they shrink
4. DWater moves into the cells, and they swell

Plasmids with an ampicillin-resistance gene are mixed with bacteria, which are then spread on a plate containing ampicillin. Why do only a few colonies grow?

1. AThe plasmid kills the bacteria that do not grow
2. BAll the bacteria die, and the colonies are fungi
3. COnly the bacteria that took up the plasmid can survive
4. DAmpicillin makes some bacteria take up the plasmid