Get premium membership and access questions with answers, video lessons as well as revision papers.
During DNA replication, the DNA makes copies of itself. This happens during the S phase of cell cycle. The replication starts in specific parts of DNA called “origins of replication.” DNA helicase- is an enzyme that opens or unzips the double helix so there are two strands ready to be replicated. SSBP are proteins that keep the strands apart from each other, and DNA topoisomerase deals with the twisting problem. the replication starts when an RNA primer attaches to the origins (because free nucleotides can not attach unless there is something to hold to). Then DNA polymerase starts attaching nucleotides to the strands so A pairs with T and G with C. it is important to mention that the replication only occurs in 5’ to 3’ direction. As we know the DNA strands are twisted in opposite direction (on in 5’ to 3’ and the other in 3’ to 5’ direction). So in one strand, DNA polymerase continuously adds nucleotides to make the new DNA. This process is fast and this is called the leading strand. But on the strand the DNA polymerase has to work kind of backwards because it has to go on the other direction in order to replicate from 5’ to 3’ direction. This is a discontinoual process and this is the lagging strand. The DNA that is made is fragmented in so called “okazaki fragments.” When the process is stoped, DNA ligase links these fragments and the DNA is replicated in two identical copies.
Mohaissack answered the question on October 4, 2017 at 08:48
- Describe the structure of DNA.(Solved)
Describe the structure of DNA.
Date posted: October 4, 2017. Answers (1)
- Name the organ that detects a change in body temperature(Solved)
Name the organ that detects a change in body temperature
Date posted: September 30, 2017. Answers (1)
- What is Respiration?(Solved)
What is respiration?
Date posted: September 28, 2017. Answers (1)
- Describe the economic importance of (i) Fungi (ii) Bacteria(Solved)
Describe the economic importance of
(i) Fungi
(ii) Bacteria
Date posted: September 28, 2017. Answers (1)
- Name two causes of allergic reactions.(Solved)
Name two causes of allergic reactions.
Date posted: September 25, 2017. Answers (1)
- Give one function of Iron as an element in human body and deficiency disease caused?(Solved)
Give one function of Iron as an element in human body and deficiency disease caused?
Date posted: September 25, 2017. Answers (1)
- State two functions of bile salts produced by liver.(Solved)
State two functions of bile salts produced by liver.
Date posted: September 25, 2017. Answers (1)
- State two common reagents for testing for the presence of proteins in a food substance.(Solved)
State two common reagents for testing for the presence of proteins in a food substance.
Date posted: September 25, 2017. Answers (1)
- What is natural selection?(Solved)
What is natural selection?
Date posted: September 25, 2017. Answers (1)
- What is oxygen debt?(Solved)
What is oxygen debt?
Date posted: September 25, 2017. Answers (1)
- State two physiological changes that take place in the human skin in order to
facilitate heat gain in the body.(Solved)
State two physiological changes that take place in the human skin in order to
facilitate heat gain in the body.
Date posted: September 25, 2017. Answers (1)
- An organ is with an exoskeleton, segmented body, two pairs of legs per segment, a pair of eyes and a pair short antennae belongs to...(Solved)
An organ is with an exoskeleton, segmented body, two pairs of legs per segment, a pair of eyes and a pair short antennae belongs to the phylum
Date posted: September 25, 2017. Answers (1)
- Explain how surface area and volume are related to temperature control in rats.(Solved)
Explain how surface area and volume are related to temperature control in rats.
Date posted: September 25, 2017. Answers (1)
- What is the significance of getting rid of the lactic acid produced during
anaerobic respiration in animals?(Solved)
What is the significance of getting rid of the lactic acid produced during
anaerobic respiration in animals?
Date posted: September 25, 2017. Answers (1)
- One can use both the nose and mouth for inhalation. Explain which is the more appropriate path of
inhalation.(Solved)
One can use both the nose and mouth for inhalation. Explain which is the more appropriate path of
inhalation.
Date posted: September 25, 2017. Answers (1)
- Name part of mammalian digestive system where the digestion of fats begins.(Solved)
Name part of mammalian digestive system where the digestion of fats begins.
Date posted: September 25, 2017. Answers (1)
- Give a reason why light stage of photosynthesis only takes place in granum of chloroplast.(Solved)
Give a reason why light stage of photosynthesis only takes place in granum of chloroplast.
Date posted: September 25, 2017. Answers (1)
- Explain what would happen to onion epidermal cells if they were placed in distilled water(Solved)
Explain what would happen to onion epidermal cells if they were placed in distilled water
Date posted: September 25, 2017. Answers (1)
- What is the biological importance of the larval stage during metamorphosis?(Solved)
What is the biological importance of the larval stage during metamorphosis?
Date posted: September 25, 2017. Answers (1)
- State the main characteristics of the five kingdoms of organisms?(Solved)
State the main characteristics of the five kingdoms of organisms?
Date posted: September 25, 2017. Answers (1)