IGCSE Biology Paper-1: Specimen Questions with Answers 153 - 154 of 208

Question 153

Edit

Question

MCQ▾

The nucleic acids that behave like enzymes are called

Choices

Choice (4)
a.Nucleases
b.Ribozymes
c.Abozymes
d.Ribose’s

Answer

b.

Explanation

  • A ribozyme is a ribonucleic acid (RNA) enzyme that catalyzes a chemical reaction. The ribozyme catalyzes specific reactions in a similar way to that of protein enzymes. Also called catalytic RNA, ribozymes are found in the ribosome where they join amino acids together to form protein chains. Ribozymes also play a role in other vital reactions such as RNA splicing, transfer RNA biosynthesis, and viral replication. The first ribozyme was discovered in the early 1980s and led to researchers demonstrating that RNA functions both as a genetic material and as a biological catalyst. This contributed to the worldwide hypothesis that RNA may have played a crucial role in the evolution of self-replicating systems. This is referred to as the RNA World Hypothesis

Question 154

Edit

Question

MCQ▾

Following diagram is showing the structure of a triglyceride.

Which of the following option is Correct?

Chemical Bond

Chemical Bond

Loading image

Choices

Choice (4)
a.A-Fatty acid chain, B-Glycerol
b.A-Glucose, B- Fructose
c.A-Glycerol, B-Fatty acid chain
d.A-Amino acid, B-Fatty acid chain

Answer

c.

Explanation

3-fatty acids are attached to a C-atom of glycerol (forming triglyceride) by Ester linkage (a weak bond, which is broken on heating), so known as esters of fatty acids with glycerol.

Triglyceride Molecule

Triglyceride Molecule

Loading image