B1 - You and your genes
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- Created by: StudentAM
- Created on: 28-04-17 20:24
What is found in the nucleus?
Genes - instructions to control how an organism develops and functions
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Types of proteins?
structural (e.g. collagen) or functional (e.g. enzymes such as amylase)
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Genes are sectons of..
very long DNA molecules that make up chromosomes in the nuclei of cells
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What determines some characteristics?
by genes (e.g. dimples), some are determined by environmental factors (e.g. scars), and some are determined by a combination of genes and the environment (e.g. weight) and some are determined by several genes working together (e.g. eye colour).
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What do body cells contain?
pairs of chromosomes and that sex cells contain only one chromosome from each pair
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What do chromosomes have?
carry the same genes in the same place, but that there may be different versions of genes called alleles
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What do individuals usually have in body cells?
two alleles of each gene can be the same (homozygous) or different (heterozygous)
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What happens during sexual reproduction?
genes from both parents come together and produce variation in the offspring
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Why do some offspring have similarities to their parents?
because of the combination of maternal and paternal alleles in the fertilised egg
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Why do siblings differ?
because they inherit a different combination of maternal and paternal alleles
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Describe a dominant allele.
an individual with one or both dominant alleles (in a pair of alleles) will show the associated dominant characteristic
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Describe a recessive allele.
an individual with one recessive allele (in a pair of alleles) will not show the associated recessive characteristic, an individual with both recessive alleles (in a pair of alleles) will show the associated recessive characteristic.
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What are the male and female chromosomes?
Male - XY , Female - **
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What is the Y chromosome?
sex determining gene which triggers the development of testes, if absent, ovaries develop
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What is genotype?
the genetic make-up of an organism (the combination of alleles)
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What is phenotype?
the observable characteristics that the organism has.
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How are disorders caused?
by faulty alleles of a single gene. eg. Huntington’s disease and cystic fibrosis
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What are causes and symptoms of Huntington's?
caused by dominant alleles, symptoms: late onset, tremor, clumsiness, memory loss, inability to concentrate, mood changes
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What are causes and symptoms of Cystic Fibrosis?
caused by recessive alleles (one recessive alleles is a carrier), symptoms: thick mucus, difficulty breathing, chest infections, difficulty in digesting food
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Uses of genetic testing for screening adults, children and embryos.
testing embryos for embryo selection (pre-implantation genetic diagnosis), predictive testing for genetic diseases, testing an individual before prescribing drugs
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Implications for testing adults and fetuses.
risk of miscarriage as a result of cell sampling for the genetic test, false-positives & false-negatives, whether or not a pregnancy should be terminated, inform family?,
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Implications of embryo selection.
Unethical, expensive, 'Playing God', wasting other embryos, insurance companies and employers may decline.
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Describe asexual cloning
bacteria, plants and some animals can reproduce asexually to form clones (individuals with identical genes)
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What causes differentiation in clones?
Environmental factors (eg. scars, hair colour)
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How do plants produce clones?
occur naturally, producing bulbs or runners
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How do animals create clones?
naturally - when cells of an embryo separate (identical twins), artificially - when nucleus from an adult body cell is transferred to an empty unfertilised egg cell
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Types of stem cells
adult stem cells - unspecialised cells that can develop into many, but not all, types of cells. embryonic stem cells - unspecialised cells that can develop into any type of cell
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Advantages of unspecialised cells
stem cells from embryos and adults offer the potential to treat some illnesses
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What happens to the cells later on?
majority of cells of multicellular organisms become specialised during the early development of the organism.
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Other cards in this set
Card 2
Front
Types of proteins?
Back
structural (e.g. collagen) or functional (e.g. enzymes such as amylase)
Card 3
Front
Genes are sectons of..
Back
Card 4
Front
What determines some characteristics?
Back
Card 5
Front
What do body cells contain?
Back
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