Practice Pakistan's most useful MCQs for competitive exams

Sodium ions are “pumped” from a region of lower concentration to a region of higher concentration in the nerve cells of humans. This process is an example of

• (A)  Diffusion
• (B)  Passive transport
• (C)  Osmosis
• (D)  Active transport

Answer

Submitted By :Ali Uppal

It is possible to date the rocks by comparing the amount of specific radioactive isotopes they contain. Which of the statement is correct in this respect?

• (A)  Older sediment layers have equal amount of these radioactive isotopes as that of the young ones
• (B)  Older sediment layers have less amount of these radioactive isotopes as that of the young ones.
• (C)  Older sediment layers have greater amount of these radioactive isotopes as that of the young ones.
• (D)  Older sediment layers did not have these radioactive isotopes

Answer

Submitted By :Ali Uppal

Normally, in the process of osmosis, the net flow of water molecules into or out of the cell depends upon differences in the ?

• (A)  Concentration of water molecules inside and outside the cell
• (B)  Concentration of enzymes on either side of the cell membrane
• (C)  Rate of molecular motion on either side of the cell membrane
• (D)  None of these

Answer

Submitted By :Ali Uppal

The concept that various organisms dominated this planet during various geological time period and thus placing organisms in a time squence came from the studies by ?

• (A)  Environmental biologist
• (B)  Paleontologist
• (C)  Marine biologist
• (D)  Social biologist

Answer

Submitted By :Ali Uppal

Most cell membranes are composed principally of ?

• (A)  DNA ad protein
• (B)  Protein and Lipids
• (C)  Protein and Chitin
• (D)  Protein and RNA

Answer

Submitted By :Ali Uppal

Number of chromosomes in E.coli ?

• (A)  1
• (B)  2
• (C)  4
• (D)  6

Answer

Submitted By :Ali Uppal

Astronauts may use which technique to grow fruits and vegetables ?

• (A)  Tissue culture techniques
• (B)  Cloning
• (C)  Pasterisation
• (D)  Hydroponic culture technique

Answer

Submitted By :Ali Uppal

Messenger RNA is formed in_________?

• (A)  nucleus
• (B)  chloroplast
• (C)  mitochondria
• (D)  none of these

Answer

Submitted By :Ali Uppal

Production of genetically identical copies of organisms/cells by asexula reproduction is called ?

• (A)  Mitosis
• (B)  Replication
• (C)  Cloning
• (D)  Biological control

Answer

Submitted By :Ali Uppal

Co-enzyme is often formed from ?

• (A)  lipid
• (B)  protein
• (C)  inorganic ion
• (D)  vitamin

Answer

Submitted By :Ali Uppal