The capsid of a virus is the

cell wall and membrane complex.

Which statement about HIV is true?

The glycoproteins on HIV enable it to bind with receptors and co-receptors on host cells.

HIV can NOT be transmitted to infants during pregnancy or through breast milk.

The glycoproteins on HIV enable it to bind with receptors and co-receptors on host cells.

HIV attacks the circulatory system

There is now a vaccine to protect people from getting HIV.

Which structures are found in eukaryotic cells but not in a bacterial cells?

none of them are found in bacterial cells

Nitrogen-fixing bacteria

convert atmospheric nitrogen into ammonia.

repair nitrogen-damaged legume roots.

damage the environment by using atmospheric oxygen to produce toxic nitrogen compounds.

convert atmospheric nitrogen into ammonia.

convert ammonia in the soil into nitrogen gas.

Which statement about bacteria is FALSE?

Some are resistant to antibiotics

Some secrete toxins that spoil food or make people sick

Biology Pak 9 Self Check Quiz 3

1.

We know viruses are not alive because
- A.
  
  They are not cellular
- B.
  
  They cannot use energy.
- C.
  
  They cannot make proteins
- D.
  
  All of the above
Correct Answer
D. All of the above

Explanation
The correct answer is "All of the above." Viruses are not considered alive because they lack cellular structure, which is a defining characteristic of living organisms. Additionally, viruses cannot use energy on their own or produce proteins, both of which are essential processes for life. Therefore, all of the given reasons contribute to the understanding that viruses are not alive.

Rate this question:
2.

The cycle of viral infection, replication, and cell destruction is called the
- A.
  
  Lysogenic cycle
- B.
  
  Lytic cycle.
- C.
  
  Metabolic cycle
- D.
  
  None of the above
Correct Answer
B. Lytic cycle.

Explanation
The correct answer is lytic cycle. The lytic cycle refers to the cycle of viral infection, replication, and cell destruction. In this cycle, the virus attaches to the host cell, injects its genetic material, takes over the cell's machinery to produce more viral particles, and eventually causes the cell to burst, releasing the newly formed viruses. This cycle is characterized by the destruction of the infected cell and the release of viral progeny.

Rate this question:
3.

The capsid of a virus is the
- A.
  
  Protective outer coat
- B.
  
  Nucleus
- C.
  
  Cell membrane
- D.
  
  Cell wall and membrane complex.
Correct Answer
A. Protective outer coat

Explanation
The capsid of a virus refers to its protective outer coat. This coat helps to shield the genetic material of the virus, such as its DNA or RNA, from damage and degradation. It also plays a crucial role in the virus's ability to infect host cells. The capsid is made up of protein subunits called capsomeres, which come together to form a symmetrical structure around the viral genome. The protective outer coat allows the virus to survive in various environments and facilitates its entry into host cells during infection.

Rate this question:
4.

Which statement about HIV is true?
- A.
  
  HIV can NOT be transmitted to infants during pregnancy or through breast milk.
- B.
  
  The glycoproteins on HIV enable it to bind with receptors and co-receptors on host cells.
- C.
  
  HIV attacks the circulatory system
- D.
  
  There is now a vaccine to protect people from getting HIV.
Correct Answer
B. The glycoproteins on HIV enable it to bind with receptors and co-receptors on host cells.

Explanation
HIV is a virus that infects and attacks the immune system, not the circulatory system. It can be transmitted to infants during pregnancy or through breast milk, so the statement that HIV cannot be transmitted to infants in this way is false. However, the glycoproteins on HIV do enable it to bind with receptors and co-receptors on host cells, allowing it to enter and infect these cells. Currently, there is no vaccine available to protect people from getting HIV.

Rate this question:
5.

Which structures are found in eukaryotic cells but not in a bacterial cells?
- A.
  
  nuclei
- B.
  
  Membrane-bound organelles
- C.
  
  Linear chromosomes
- D.
  
  None of them are found in bacterial cells
Correct Answer
D. None of them are found in bacterial cells

Explanation
Eukaryotic cells have nuclei, membrane-bound organelles, and linear chromosomes, whereas bacterial cells do not have any of these structures. Bacterial cells have a simpler structure and lack a true nucleus, membrane-bound organelles, and linear chromosomes.

Rate this question:
6.

Nitrogen-fixing bacteria
- A.
  
  Repair nitrogen-damaged legume roots.
- B.
  
  Damage the environment by using atmospheric oxygen to produce toxic nitrogen compounds.
- C.
  
  Convert atmospheric nitrogen into ammonia.
- D.
  
  Convert ammonia in the soil into nitrogen gas.
Correct Answer
C. Convert atmospheric nitrogen into ammonia.

Explanation
Nitrogen-fixing bacteria have the ability to convert atmospheric nitrogen into ammonia. This process is known as nitrogen fixation and is essential for plants, particularly legumes, to obtain the nitrogen they need for growth. The bacteria form a symbiotic relationship with the plant, colonizing their roots and converting the nitrogen gas in the air into a form that the plants can use. This conversion of atmospheric nitrogen into ammonia is a crucial step in the nitrogen cycle and helps to maintain the availability of nitrogen in the soil for plant growth.

Rate this question:
7.

Which statement about bacteria is FALSE?
- A.
  
  Some are resistant to antibiotics
- B.
  
  Some secrete toxins that spoil food or make people sick
- C.
  
  Some are eukaryotic
- D.
  
  Some are parasites
Correct Answer
C. Some are eukaryotic