Top answers

Biology
A Level

Describe 3 differences between mitosis and meiosis

Mitosis consists of one stage whereas meiosis consists of two stages.

Mitosis produces diploid cells (46 chromosomes) whereas meiosis produces haploid cells (23 chromosomes).

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RC
Answered by Runzhi C. Biology tutor
270734 Views

Describe how a heartbeat is initiated and coordinated?

The sinoatrial node (SAN) sends a wave of electrical activity across the atria causing atrial contraction. The non-conducting tissue stops the immediate contraction of the ventricles. The atrioventricular...

DY
Answered by Dharani Y. Biology tutor
41550 Views

What is Krebs cycle and what is its role in aerobic respiration

Krebs cycle is a series of reactions that take place in the mitochondria of most living cells and result in the production of energy during aerobic respiration. During Krebs cycle oxygen is metabolised...

AT
10773 Views

What is the role of Tropomyosin in myofibril contraction?

Tropomyosin helps to regulate myofibril contraction. Before contraction, tropomyosin covers the myosin binding sites on the actin molecule, preventing the myosin heads from binding. During contraction, ca...

LH
Answered by Laura H. Biology tutor
9827 Views

Why is sickle cell disease most common among people living in tropical regions, and their descendants?

Sickle cell disease is caused by a recessive allele of the haemoglobin gene. When two copies are present (i.e. it is homozygous), many red blood cells become sickle-shaped, leading to disease.

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SG
Answered by Sean G. Biology tutor
17480 Views

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