ورقة عمل الأحياء لامتحانات القبول في التمريض مع الإجابات

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

1. AChitin
2. BPeptidoglycan
3. CKeratin
4. DCellulose

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

1. ALipase
2. BHelicase
3. CLigase
4. DAmylase

What is an organism's genotype?

1. AThe environment in which it lives
2. BThe traits that can be seen or measured
3. CThe number of cells in its body
4. DThe alleles it carries for a trait

Sickle cell disease is caused by a single base change that replaces one amino acid in haemoglobin. What type of mutation is this?

1. AA frameshift mutation
2. BA silent mutation
3. CA nonsense mutation
4. DA missense mutation

Why are stains such as iodine or methylene blue added to cells on a microscope slide?

1. ATo keep the cells alive for longer
2. BTo make structures easier to see
3. CTo make the cells divide
4. DTo make the cells larger

When most people in a community are vaccinated, people who cannot be vaccinated are also protected. Why?

1. AThe pathogen has too few hosts to spread easily
2. BThe vaccine spreads from person to person
3. CThe pathogen mutates into a harmless form
4. DVaccinated people make antibodies for others

An Rh-negative mother gives birth to an Rh-positive baby. Why could a later Rh-positive pregnancy be at risk?

1. AHer red cells may become Rh positive after the birth
2. BThe second baby will be unable to make any red cells
3. CThe first baby's antibodies remain in her blood and attack her
4. DShe may have made anti-D antibodies that cross the placenta

Under the microscope, homologous chromosomes are moving to opposite poles, and each is still made of two chromatids. Which stage is this?

1. AAnaphase of mitosis
2. BProphase of mitosis
3. CAnaphase II of meiosis
4. DAnaphase I of meiosis