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

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

1. AHelicase
2. BLigase
3. CAmylase
4. DLipase

A solution has a pH of 3. How is it described?

1. AIsotonic
2. BAcidic
3. CBasic
4. DNeutral

Какая структура есть у растительных клеток, но отсутствует у животных?

1. AРибосома
2. BКлеточная мембрана
3. CКлеточная стенка
4. DМитохондрия

A bone marrow transplant can treat some blood cancers. Why does it work?

1. AThe donor red cells divide to make more red cells
2. BThe donor marrow contains antibiotics that kill cancer
3. CThe transplant replaces the patient's bones
4. DThe donor stem cells produce new, healthy blood cells

Why can an electron microscope show more detail than a light microscope?

1. AElectron microscopes use stronger glass lenses
2. BElectrons are brighter than light
3. CElectron microscopes use living cells only
4. DElectrons have a much shorter wavelength than light

Why do many plants close their stomata on hot, dry days?

1. ATo reduce water loss
2. BTo take in more carbon dioxide
3. CTo speed up photosynthesis
4. DTo release more oxygen

How does the CRISPR-Cas9 gene-editing system find the right place to cut DNA?

1. AIt reads the amino acid sequence of the protein
2. BIt binds only to the start codon of every gene
3. CThe Cas9 protein cuts DNA at random sites
4. DA guide RNA pairs with the matching DNA sequence

Which statement correctly compares DNA replication and transcription?

1. AReplication copies all the DNA; transcription copies one gene
2. BBoth take place on ribosomes in the cytoplasm
3. CBoth use thymine and deoxyribose in the new strand
4. DReplication makes RNA from DNA; transcription makes DNA from RNA