| What are gametes? | Gametes are single, not paired chromosomes that such as sperm and egg cells in humans. |
| What does meiosis produce and where does it take place? | Meiosis produced non-identical cells. And meiosis only takes place in reproductive organs such as the human testes and ovaries. |
| What is fertilisation? | Fertilization is the fusion of male gametes such as sperm cells or pollen cells with female gametes such as egg cells, therefore in sexual reproduction there the offspring receives genetic information from both male and female parents |
| Why can variation be seen in offspring? | Variation can be seen in offspring because all gametes are different |
| How does asexual reproduction differ from sexual reproduction? | Asexual reproduction differs from sexual reproduction as it only involves one parent and does not involve gametes. Therefore there is no mixing of genetic information so offspring are genetically identical or clones. So asexual reproduction mush happen through mitosis. An example of asexual reproduction is when the kalanchoe plant reproduces by forming tiny buds at the edge of its leaves, that drop off and grow into new clone plants. |
| What happens in meiosis? | In meiosis all the chromosomes are copied and the cell divides into two.
Now these cells divide again forming the gametes, with singular not paired chromosomes. Meiosis therefore halves the number of chromosomes and produces four gametes from one original cell, that are all have different alleles. |
| What happens to gametes in and after fertilisation? | In fertilisation, the single male and female gametes pair together to form zygotes, so in fertilisation chromosomes become pairs. And after fertilisation the new zygotes divide by mitosis and produce a clump of identical cells called an embryo. Then as the embryo develops, its cells differentiate, and form different cell types, such as nerve and muscle cells. |
| Why is DNA a genetic material? | DNA is a genetic material because it determines inherited features |
| What does the structure of DNA contain? | The structure of DNA contains two strands of a polymer, which are made up of lots of tiny, joined molecules, that wrap around each other to form a double helix. |
| What does the blood type gene encode? | The blood type gene encodes the sequence of amino acids for the protein that determines blood type |
| What is the genome? | The genome is the entire genetic material of an organism |
| What are the benefits of scientists having studied the entire human genome? | The benefits of scientists having studied the entire human genome include understanding it allows for genes linked to diseases to be searched for e.g. Alzheimer’s and cancer, it allows for inherited disorders to be understood and treated e.g. cystic fibrosis, and it also allows for human migration patterns from the past to be traced to help people discover their ancestry. |
| What are alleles? | Alleles are different versions of a gene |
| What does the genotype show? | The genotype shows what alleles are present in a person, such as their dominant and recessive traits |
| What are heterozygous and homozygous alleles and when will they show? | Heterozygous alleles are when a dominant and recessive allele are present in the phenotype such as Ee.
While homozygous alleles are when two of the same alleles are present in the phenotype e.g. ee or EE. Because dominant alleles will always show when present, recessive alleles will only show when alleles are homozygous. |
