Fichas
GCSE Biology B1 (OCR)
Fichas del conjunto (40)
- 1What is a fertilised cell called?A zygote.
- 2Where are the instructions to control how an organism _______ and ______ found? What are these called?Function + Develop
Nucleus
Genes - 3What are genes?Instructions for a cell that describe how to make proteins. They control which protein a cell makes.
A gene is a section of DNA molecule. - 4Proteins may be ________ or _______. What is the difference between these?Functional (eg. collagen) or Structural (eg. enzymes such as amylase).
Structural proteins are needed to build the body - collagen is the protein found in tendons. Functional proteins are needed to take part in the chemical reactions of the body. - 5What are chromosomes made up of?Very long DNA molecules.
- 6What are some characteristics determined by.... Genes? The Environment? Both?Eye colour, nose shape, blood group, gender, freckles.
Scars, hair length, tattoos, language.
Hair colour, skin colour, height, eye sight, foot size, personality. - 7Body cells contain pairs of chromosomes. How many of each pair do sex cells contain?One
- 8Why might the genes in a pair not be exactly the same?Because they contain different versions of the same gene called alleles.
- 9The alleles you inherit is called your _______.Genotype
- 10Your _______ is what you look like.Phenotype
- 11How many copies of a dominant allele to have its feature? And a recessive allele?One dominant allele.
Two recessive alleles. - 12How many alleles does a person usually have for each gene?Two
- 13Define Homozygous. Define Heterozygous.Homozygous = The two alleles of each gene are the same (eg. J, J)
Heterozygous = The two alleles of each gene are different (eg. J, j) - 14Why do offspring have similarities to their parents?Because there is a combination of maternal and paternal alleles in the fertilised egg.
- 15Why do different offspring from the same parents differ from each other?Because they inherit a different combination of the maternal and paternal alleles.
- 16How many dominant alleles do you need to show the associated characteristic? Recessive alleles?Dominant = One
Recessive = Two - 17Which sex chromosomes do males have? Females?Male = XY
Female = XX - 18How does the Y chromosome make a baby male?The SRY gene on the Y chromosome triggers the development of testes. Testes produce androgens (male sex hormones) which make the embryo develop into a male.
- 19What are Huntington's disease and cystic fibrosis caused by? Dominant or recessive alleles?Faulty alleles of a single gene.
Huntington's = Dominant
CF = Recessive - 20What are the symptoms of Huntington's disease?Late onset, tremor, clumsiness, memory loss, inability to concentrate, mood changes.
- 21What are the symptoms of Cystic Fibrosis?Thick mucus, difficulty breathing, chest infections, difficulty digesting food.
- 22What are some treatments for cystic fibrosis?- Pre-digested food or tablets (eg. milkshakes)
- Being put on oxygen
- Sport and fitness - 23What is the danger of carrying a recessive allele?The person won't show the symptoms of the disorder, but they are a carrier and could pass it onto their offspring.
- 24What are the uses of genetic testing for screening adults, children, and embryos?- Testing embryos for embryo selection (PGD)
- Predictive testing for genetic diseases
- Testing before prescribing drugs - 25Amniocentesis: How? When? Risks?How: Syringe extracts amniotic fluid, which contains fetal cells. These cells can then be tested.
When: 15-18 weeks.
Risks: 1% miscarriage risk. Small risk of infection. Results not 100% reliable. - 26Chronic Villus Sampling (CVS) How? When? Risks?How: Sample of placenta is extracted through the abdomen or the cervix, and it is then tested.
When: 10-12 weeks.
Risks: 2% miscarriage risk. Results not 100% reliable. - 27What is genetic screening?Genetic testing the whole population, or large groups.
- 28What is pre-implantation genetic diagnosis (PGD)?Several eggs are released and collected by a doctor. Sperm fertilises the eggs in a petri dish (IVF). Embryos reach the eight-cell stage, and one cell is taken from each. The cells are tested for the specific allele. Only embryos without the allele are implanted in the uterus.
- 29What are the implications that need to be considered when testing adults a fetuses for alleles that cause genetic disorders?- Risk of miscarriage as a result of cell sampling
- Results may not be accurate (FP, FN)
- Whether or not to have children
- Whether a pregnancy should be terminated
- Whether other members of the family should be informed - 30What are the implications of genetic testing by insurance companies?- They might not insure someone, or they might charge a high premium.
- People won't have genetic tests because they fear the insurance company will find out. - 31What are the implications of genetic testing by employers?- Someone might not be hired because they have a certain genetic disease, which would cost the company money.
- 32What are the implications of genetic testing by the police?- There could be a national DNA database, which allows the police to catch criminals much more easily.
- 33What is a clone?An individual with identical genes to another.
- 34Bacteria, plants, and some animals can reproduce _______ to form clones. How does this happen?Asexually
The single cell divides to from two new cells. The two cells' genes are identical. - 35Any differences between clones are due to............ environmental factors.
- 36What are some examples of plants producing clones naturally?Bulbs and runners.
- 37How do clones of animals occur?- Naturally, when cells of an embryo separate, forming identical twins.
- Artificially, when the nucleus from an adult body cell is transferred to an empty unfertilised egg cell. - 38What is the difference between a____ and e______ stem cells?Adult stem cells are unspecialised cells that can develop into many, but not all, types of cell. (eg. brain, heart, bone marrow).
Embryonic stem cells are unspecialised cells that can develop into any type of cell. - 39Give an example of when adult stem cells are used.Adult stem cells from the bone marrow can be used to treat patients with leukemia, which is cancer of the blood.
- 40What happens when someone else's cells are used in a transplant?They are rejected.
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- Descripción
- A set of flashcards for GCSE Biology B1 on the OCR exam board. Questions relate specifically to the specification.
- Creado por
- Usman Rauf
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- Creado por Josh Price · 16 abr 2015
- Copiado por Usman Rauf · 16 abr 2015
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