B1

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  • Created by: Faith16
  • Created on: 14-03-16 18:24
What does the nucleus contain in a cell?
Genetic material
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What is genetic material arranged in and how many pairs are there?
Chromosomes - 23 pairs
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What is each chromosome made from?
One long molecule of DNA thats coiled up
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What is a gene?
A short length of a chromosome
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What do genes control?
Development of different characteristics
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How do characteristics depend on proteins?
Structural proteins found in skin, hairs, blood and cytoplasm of cells (e.g. collagen- tendons,bones and cartilage). Functional proteins like enzymes (e.g. amylase breaks starch into maltose)
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What is a genotype?
All the genes an organism has
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What is a phenotype?
Characteristics the organism displays e.g. blond hair
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Give examples of a characteristics cause by genes, environment and both
Gene- dimples. Environment- scar. Both- Weight (e.g. parents both skinny you will most likely be skinny)
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What happens during sexual reproduction?
23 chromosomes in the sperm cells combine with the 23 chromosomes in the egg cell.
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What are alleles?
Different versions of the same gene.
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For two chromosomes in a pair, what is always in the same place?
Same genes which are found in the same place
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Why do children resemble both their parents but are not identical?
Because they get half of their genes from parent- haven't got all the same alleles
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Why do people not look the same?
As there are about 8 million different combinations of genes from the separate 23 chromosomes from the egg and sperm cells (also any sperm cell can hit the egg cell)
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How many copies of a gene do you have?
2
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What is homozygous?
Two of the same alleles for a particular gene
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What is heterozygous?
Two different alleles for a particular gene
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What is dominant and recessive?
Dominant is shown through two dominant alleles or a dominant and a recessive. Recessive allele is only shown through two recessive alleles.
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What are dominant and recessive alleles represented as?
Dominant- Capital letter. Recessive- Lower case letter.
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What is a genetic diagram?
A diagram which shows the possibilities of having a certain phenotype through the different arrangement of genotypes.
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What a punter squares?
Another form of genetic diagrams
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How do chromosomes control the sex of someone?
The 23rd chromosome is a sex chromosome as it it either XY (male) or ** (female).
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What does the male Y chromosome cause?
Causes a specific protein to be produced making the zygote develop testes which produce male sex hormones (females do not have this and jut develop ovaries and the rest of the female reproductive system)
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How can some disorders be inherited?
By one or both parents carrying a faulty gene.
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Name two different types of genetic disorders.
Cystic fibrosis and Huntington's disease (caused by a faulty allele of a single gene)
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What are most faulty (defective) alleles?
Recessive
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What is cystic fibrosis and what are the symptoms?
Genetic disorder of the cell membranes. Thick sticky mucus in air passages, gut and pancreas, breathing difficulty, chest infections (painful coughing) and difficulty in digesting food (short and skinny as a result)
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What are carrier?
People who carry a faulty gene.
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How much chance is there of someone having cystic fibrosis if both parents are carriers?
1 in 4
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What is Huntington's caused by?
A dominant allele (50% chance with only one parent as a carrier)
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What are the symptoms of Huntington's disease?
Tremors, clumsiness, memory loss, mood changes and poor concentration - no cure. (late onset normally 40)
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What can genetic testing be used on and how?
Embryos- IVF (used for carriers- only healthy embryos are chosen to be implanted into mother womb others discarded). Children and Adults- Carry certain alleles and tested before drug is prescribed to see how it will affect them.
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What is a false positive and a false negative?
False positive- telling someone they don't have a certain allele when they do. False negative- telling someone they don't have a certain allele when they do.
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What are the issues surrounding genetic testing?
Not 100% accurate, not 100% safe (e.g. 0.5-1% miscarriage), cause other people to get tested, right to know of someones genetic disease(?), terminate pregnancy (?), may cause discrimination, insurance companies might refuse to give life insurance.
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What are clones?
Genetically identical organisms.
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What are differences between clones due to?
Environment
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How does nature create clones?
Asexual reproduction e.g. bacteria divide into two, plants, and some animals such as greenfly (can produce sexual as well)
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How do plants reproduce asexual?
Some produce horizontal stems called runners that move from the base of the plant to form a new clone (e.g strawberry plants). They also produce underground fleshy structures called bulbs where they grow to form clones (e.g. garlic)
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How are identical twins made?
When a single egg fertilised by sperm beings to develop as normal but then splits into to separate embryos to create two genetically identical babies.
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How can scientists create animal clones?
By removing the nucleus from an egg cell leaving the egg without any genetic information. A nucleus from an adult donor cell is inserted in its place so when the cell is stimulated it starts dividing as if it was a normal embryo.
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What are stem cells?
Unspecialised cells that can develop into different types of cells depending on their instructions.
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What are the two main types of stem cells?
Embryonic (potentail to turn into any cell) and Adult (maintaining and repairing old and damaged tissues and specialise into many types of cells)
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How are stem cells used to treat illnesses?
Blood diseases e.g. sickle cell anaemia can be treated with a bone marrow transplant. Embryonic stem cells can replace faulty cells e.g. heart muscle cells, insulin-producing cells and nerve cells (still being researched)
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Other cards in this set

Card 2

Front

What is genetic material arranged in and how many pairs are there?

Back

Chromosomes - 23 pairs

Card 3

Front

What is each chromosome made from?

Back

Preview of the front of card 3

Card 4

Front

What is a gene?

Back

Preview of the front of card 4

Card 5

Front

What do genes control?

Back

Preview of the front of card 5
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