IGCSE Biology Paper-1: Specimen Questions with Answers 153 - 154 of 208
Question 153
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
Question MCQ▾
Following diagram is showing the structure of a triglyceride.
Which of the following option is Correct?
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.