6184981
Description
Flashcards by Mel Hughes, updated more than 1 year ago
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Created by Mel Hughes
over 9 years ago
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| Question | Answer |
| Which type of cell division produces two identical cels from the original cell? | Mitosis |
| What type of cells are produced by meiosis? | Sex cells or gametes, eggs and sperm |
| Explain how four gametes are formed from one cell | There are two sets of cell division. A body cell divides into two each divides again |
| Where are stem cells found in adult humans? | Bone marrow |
| Which scientist worked out how characteristics are inherited? | Mendel |
| What does a gene code for? | The order of amino acids in a protein |
| Which sex chromosomes are found in human males? | X and Y |
| What is meant by the term 'phenotype'? | This is a description of the physical characteristics |
| Name a genetic disorder which is controlled by a dominant allele | Polydactyly |
| What are the chances of a child having cystic fibrosis if one parent has the disorder and the other parent is heterozygous? | 50%, as one parent (cc) has to pass on the allele, the other parent (Cc) has a 50% risk of passing it on; the child is either Cc or cc |
| What is embryo screening? | Tests are carried out on the embryo to diagnose possible disorders |
| Why do cells divide by mitosis? | To produce identical cells for growth and to replace cells |
| How many chromosomes does a human have in each body cell? | 23 pairs (or 46) |
| Which type of cell division produces sex cells? | Meiosis |
| What molecule are genes made of cells? | DNA |
| What are 'alleles'? | Different forms of a gene |
| Why does sexual reproduction result in variation? | The genetic material from two parents is brought together when the sperm and egg nuclei fuse |
| Explain why offspring produced by asexual reproduction are genetically identical | They are produced by mitosis. Cells from one parent divide to produce identical cells |
| What is meant by the term 'genotype'? | The types of genes present in the cells |
| What do we mean by a 'heterozygous' individual? | The individual has one dominant and one recessive allele for a condition |
| What are the chances of a child having polydactyly if one parent is heterozygous and the other parent is homozygous recessive? | 50%, as the dominant gene controls the condition; a child has a 50:50 chance of inheriting the allele from the heterozygous parent |
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