12678102
Description
Flashcards by Mrs Z Rourke, updated more than 1 year ago
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Created by Mrs Z Rourke
about 6 years ago
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| Question | Answer |
| Describe the structure of DNA | DNA contain four bases - adenine, thymine, guanine and cytosine. These bases pair up (A-T, C-G) to bases on another strand with hydrogen bonds to form a double helix. |
| What is a triplet code? | Each triplet code identifies a particular amino acid. |
| What is genetic profiling? | Genetic profiling is the analysis of a person's DNA |
| How is a genetic profile produced? | DNA is cut into short pieces using enzymes. The cut up pieces of DNA are then placed in the wells of a gel and an electric current is passed through (electrophoresis). The DNA travels up the gel - smaller fragments go further. |
| What can genetic profiling be used for? | Samples can be compared for paternity tests, criminal cases and in comparisons between species for classification purposes. |
| What is a gene? | Sections of DNA molecules that determine inherited characteristics |
| What is an allele? | Different forms of a particular gene e.g. eye colour - blue, brown |
| What is a chromosome? | A length of DNA that contains many genes, found in the nucleus and visible during cell division |
| In genetics, what is meant by the term dominant? | An allele that shows the phenotype whenever it is present (shown by a capital letter) |
| In genetics, what is meant by the term recessive? | An allele that is hidden when a dominant allele is present (shown by a lower case letter) |
| In genetics, what is meant by the term homozygous? | Contains two identical alleles for the gene concerned (e.g. BB, bb) |
| In genetics, what is meant by the term heterozygous? | Contains two different alleles for the gene concerned (e.g. Bb) |
| In genetics, what is meant by the term genotype? | The genetic makeup of an individual |
| In genetics, what is meant by the term phenotype? | The description of the way the genotype ‘shows itself’ (e.g. blue eyes, red flowers) |
| In genetics, what is meant by the term F1/F2? | Short for first generation (F1) and second generation (F2) |
| In genetics, what is meant by the term selfing? | A technique by which pollen from a plant is used to fertilise ovules in flowers of the same plant |
| If a tall plant (TT) is crossed with a short plant (tt), what is the percentage chance of a tall plant being produced? |
100% chance of plant being tall
Image:
Tt (binary/octet-stream)
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| If a person with blue eyes (bb) has child with a person with brown eyes (Bb), what is the percentage chance of having a child with brown eyes? |
50% chance of having a child with brown eyes
Image:
Bb (binary/octet-stream)
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| Tall allele is dominant, short allele is recessive. If a homozygous recessive plant is crossed with a heterozygous plant, what is the ratio of tall plants to short plants produced? |
1:1 (2:2)
Image:
Tt1 (binary/octet-stream)
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| How many pairs of chromosomes do humans have? | 23 pairs |
| On what pair of chromosomes is the sex of the person determined? | 23rd pair |
| What are the alleles for male and female? | Male = XY Female = XX |
| What is genetic modification? | Genes can be transferred from one organism to another. |
| What are the advantages of genetic modification? | Depends on the organism in question but could include disease resistance and increased yield |
| What are the disadvantages of genetic modification? | Depends on the organism in question but could include effects on health and the environment (e.g. give rise to super weeds) |
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