Question
The graph shows how the rate of photosynthesis of a green plant varies with CO2 concentration at two different light intensities. The temperature is kept constant at 20°C.
What is the limiting factor at X?
A. Chlorophyll
B. Light intensity
C. Temperature
D. \(CO_2\) concentration
Answer/Explanation
Question
The table shows the estimated total number of genes in several organisms.
What can be deduced from the information in this table?
A. Throughout evolution, the number of genes increases.
B. The domestic dog is more closely genetically related to the fruit fly than to the human.
C. The number of genes does not determine evolutionary success.
D. Humans produce about half as many proteins as rice.
Answer/Explanation
Ans: C
Question
Chromosome numbers vary between species. Which statement refers to humans?
A. An egg cell has 22 autosomes.
B. A sperm cell has 23 autosomes.
C. An egg cell has two X chromosomes.
D. A zygote has two autosomes.
Answer/Explanation
Ans:
Question
Which process occurs in meiosis but not in mitosis?
A. Attachment of spindle fibres to the centromeres of each chromosome
B. Movement of homologous chromosomes to opposite ends
C. Replication of DNA prior to the start of cell division
D. Separation of sister chromatids during anaphase
Answer/Explanation
Ans:
Question
Which curve shows the concentration of product during the course of an enzyme-catalysed
reaction?