The enzyme that removes RNA primers and replaces them with DNA during replication is:
A. DNA polymerase I
B. DNA polymerase III
C. Ligase
D. Helicase
Answer: Option A
Solution (By JKSSB Mock Tests)
In prokaryotes, DNA polymerase I has 5'→3' exonuclease activity that removes the RNA primer and fills the gap with DNA. DNA polymerase III adds nucleotides to the growing strand. Ligase seals the nicks. Helicase unwinds DNA. In eukaryotes, RNase H removes primers and DNA polymerase δ fills the gap.
Explanation:
Budding is an asymmetric division where a new yeast cell forms as a small bud on the parent, eventually pinching off. Binary fission is symmetric splitting (bacteria), fragmentation is breaking into pieces, spore formation involves spores. Budding can occur in some hydra as well.
Consider statements about human skeleton: 1. The human skull has 22 bones. 2. The femur is the longest bone. 3. Ribs are attached to the sternum directly or indirectly. Which are correct?
Explanation:
The human skull consists of 22 bones (8 cranial and 14 facial). The femur (thigh bone) is the longest and strongest bone in the human body. Humans have 12 pairs of ribs; the first 7 are true ribs (direct attachment), next 3 are false ribs (indirect), and last 2 are floating. All statements are anatomically correct.
Explanation:
Vitamin D (cholecalciferol) is unique as it can be synthesized in the skin from 7-dehydrocholesterol in the presence of UV-B radiation. It acts as a hormone to regulate calcium and phosphate homeostasis. It must be activated in the liver and kidneys. It is also obtained from dietary sources like fatty fish, egg yolk. Deficiency causes rickets/osteomalacia.
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