H
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A complex molecule found in red blood cells. It is composed of 4 peptide chains and 4 haem groups. Each haem group contains an atom of iron. Haemoglobin contributes the red colour to blood. Its main purpose is to carry respiratory gases - oxygen from the lungs to the tissues, and carbon dioxide from the tissues to the lungs. It also works as a buffer to stabilise the pH of blood.
Half the usual number of chromosomes. Most human cells contain 46 chromosomes in their nucleus - this is the diploid number. When gametes are being prepared by meiosis, that number is reduced to 23. - half the usual number of chromosomes. Most human cells contain 46 chromosomes in their nucleus - this is the diploid number. When gametes are being prepared by meiosis, that number is reduced to 23.
A set of genetic markers that lie close together on a chromosome and are inherited together. Haplotypes can be studied to unravel the reasons why some people are more susceptible than others to conditions such as diabetes and heart disease.
These are proteins associated with DNA in chromosomes. The DNA molecule is wrapped around the histones to form bead-like nucleosomes. histones.
A chemical released into the blood from an endocrine gland (ductless gland). The hormone travels around the body and produces changes in target cells. Target cells are able to recognise the hormone as a signal and respond by becoming more or less active, beginning or stopping cell division, taking glucose from the blood, or some other change in behaviour. There are two main classes of hormones: those which are protein-like, and those which are steroids. Membership of one or other chemical class will influence the way the hormone acts upon the cell. hormone - a chemical released into the blood from an endocrine gland (ductless gland). The hormone travels around the body and produces changes in target cells. Target cells are able to recognise the hormone as a signal and respond by becoming more or less active, beginning or stopping cell division, taking glucose from the blood, or some other change in behaviour. There are two main classes of hormones: those which are protein-like, and those which are steroids. Membership of one or other chemical class will influence the way the hormone acts upon the cell.