B1-You and Your Genes

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  • Created by: ElishaG
  • Created on: 11-05-16 16:04
Where is genetic material in a cell?
The nucleus.
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How many chromosomes do humans have?
23 pairs (46 chromosomes).
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What is a chromosome?
A very long DNA molecule that's coiled up (the coiling is what gives chromosomes their shape).
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What do genes control?
The development of characteristics e.g. hair colour. And how an organism functions.
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What are alleles?
Different versions of the same gene, for example blue or brown eyes.
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What are genes?
The instructions for making proteins.
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What are proteins?
The building blocks of cells.
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What does having different versions of proteins mean?
We end up with different characteristics.
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What are the two types of protein?
Structural (hair,skin,blood,cytoplasm) and functional.(enzymes)
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Give examples of structural proteins
Collagen, found in tendons, bones and cartilage. Keratin, found in hair and nails.
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Give an example of a functional protein.
Enzymes(break down food molecules), amylase is a digestive enzyme, breaks starch down into maltose.
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What is a genotype?
All of the genes an organism has.
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What is a phenotype?
The characteristics an organism displays.
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What is variation in characteristics caused by?
Genes e.g. dimples and environment e.g. scars.
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Give an example of a characteristics that can be caused by both environmental and genetic factors.
Weight, height etc. If both parents are skinny, you probably will be, but not if you only eat donuts.
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What are gametes?
Egg and Sperm cells.
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How many chromosomes do gametes have?
23 chromosomes (when sperm fertilises egg the chromosomes will combine to have a total of 46 chromosomes).
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True or False- two chromosomes in a pair always carry the same genes?
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Why do children resemble their parents but identical to none of them?
Get alleles from each parent, don't look identical as get half from mother, half from father. Every child has unique combination of alleles so no two people are identical (except identical twins).
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Why are the chances of siblings being identical minuscule?
There are millions of combinations of chromosomes for egg and sperm, it is extremely unlikely that an egg cell will be fertilised by an identical sperm cell.
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What are you if you have two alleles the same for a particular gene?
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What are you if you have two different alleles for a particular gene?
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What can alleles be?
Dominant(shown by capital letters) or recessive (shown by lower case letters)
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In order to show a recessive characteristic, which alleles do you need?
Two recessive.
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In order to show a dominant characteristic, which alleles do you need?
Either two dominant or a dominant and recessive.
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What is gender determined by?
a gene.
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Which chromosomes determine gender?
23rd pair.
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What are the letters for male chromosomes?
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What are the letters for female chromosomes?
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Explain how a gene determines gender.
1)Gene causes specific protein to be produced.2)Protein causes androgen+ testes to develop instead of ovaries.3)Testes then produce male sex hormones-make rest of male system develop.4)In females, protein not produced, so embryo develops ovaries etc.
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What is the name of the gene that triggers the development of testes?
the Sex-determining region (SRY)
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What are both Huntington's and Cystic Fibrosis caused by?
A faulty allele of a single gene.
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Is the allele for Cystic Fibrosis dominant or recessive?
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What are the symptoms of Cystic Fibrosis?
Thick sticky mucus in air passages, gut and pancreas. Breathing difficulties. Chest infections.Difficulty in digesting food.
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When do people realise they have Cystic Fibrosis?
From Birth.
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How many people carry the allele for cystic fibrosis?
1 in 25.
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What are carriers?
people with one copy of a recessive allele.
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Is the allele for Huntington's Disease dominant or recessive?
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What are the symptoms of Huntington's?
Tremors,clumsiness,memory loss, mood changes and poor concentration. No cure.
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When do the symptoms of Huntington's appear?
Late onset- 40's.
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Who can have a genetic test?Why?
Embryo-test for genetic conditions. Child-Paternity test. Adult-See effect of drugs.
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When are embryos tested?
When they're produced by IVF. Known as pre-implantation genetic diagnosis, very important if parents carry alleles for genetic disorder.Healthy ones implanted.
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What are the issues surrounding genetic testing?(there are 7)
1)Not 100% accurate (false positives/negatives)2)Increase risk of miscarriage.3)who should be told?4)Is it right for someone with a condition to have children?5)Should they terminate pregnancy?6)Job discrimination.7)Insurance problems.
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What are clones?
Genetically identical organisms.
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What does asexual reproduction mean?
There is only one parent.
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What can reproduce asexually?
Bacteria, some plants and some animals to form clones.
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Why are there differences in identical twins?
Because of their environment.
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How do bacteria reproduce asexually?
They divide into two.
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How do plants reproduce asexually?
1)Runners(horizontal stems) that move from base of plant to form new clones e.g. strawberry plants.2)Bulbs (underground fleshy structures) grow to form new, identical plant, e.g. garlic.
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How does the female greenfly reproduce asexually?
Lay eggs that develop into identical females. Can also reproduce sexually.
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How are identical twins formed?
1)Single egg fertilised by single sperm- embryo starts to develop as normal.2)Embryo splits into two-two separate embryos begin to develop.3)Two embryos are genetically identical- two identical babies born.
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How can scientists make clones in a lab?
1)Nucleus of egg cell is removed.2)Nucleus from adult donor inserted into egg cell.3)Cell then stimulated so it starts to develop like a normal embryo.4)Embryo produced is genetically identical to donor cell.
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When do most cells become specialised?
During early development of an organism (8 cell stage).
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What are unspecialised cells?
Cells that can develop into different types of cells depending on the instructions they are given. They're called stem cells.
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What are the two main types of stem cells?
Embryonic and adult.
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What are embryonic stem cells?
Unspecialised cells found in early embryos. Stem cells removed from embryo, embryo destroyed. Exciting to doctors and researchers as they can turn into any type of cell.
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What are adult stem cells?
Unspecialised cells in adult animals.Involved in repairing and maintaining old and damaged cells. Can't turn into all cell types.Adult stem cells can be safely removed from patient e.g. extracting bone marrow.
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Which type of stem cells are already used in medicine?Give example.
Adult stem cells to cure diseases. e.g. people with blood diseases can be treated by bone marrow transplants. Bone marrow contains adult stem cells that can turn into new blood cells to replace faulty ones.
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How could embryonic stem cells be used in medicine?Give examples.
Used to replace faulty cells, e.g.heart muscle cells for people with heart disease,insulin producing cells for people with diabetes, nerve cells for people paralysed by spinal injuries etc
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Why aren't embryonic stem cells being used in medicine now?
Treatments are still being researched.
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Other cards in this set

Card 2


How many chromosomes do humans have?


23 pairs (46 chromosomes).

Card 3


What is a chromosome?


Preview of the front of card 3

Card 4


What do genes control?


Preview of the front of card 4

Card 5


What are alleles?


Preview of the front of card 5
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