OCR Biology B1 Flashcards

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What are Genes?
A short length of chromosome that controls the development of different characteristics. Each gene is a code for making a certain protein.
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Name two different kinds of protein.
Structural proteins such as as collagen found in tendons, bones and cartilage. Functional proteins such as the digestive enzyme amylase.
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Where are chromosomes found and what are they?
Chromosomes are found in the nucleus of a cell. They are genetic material, 1 per parent per pair, of which there are 23 pairs.
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Explain genetic variation in sex cells.
During fertilisation, the egg and sperm cell each bring 23 chromosomes each with their own version of the same gene (an allele). As the two sex cells fuse, the baby could sperm could have an X (female) or a Y (male) chromosome.
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What is the difference between a Genotype and a Phenotype?
A Genotype is all the genes an organism has while a Phenotype are the physical characteristics of an organism.
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What is the difference between Inherited and Environmental characteristics?
Inherited characteristics are controlled by your genes while Environmental characteristics are controlled by your environment.
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What is the difference between Homozygous and Heterozygous?
Homozygous are 2 alleles which are the same while Heterozygous are 2 alleles which are different.
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What is the difference between Dominant and Recessive alleles?
A Dominant allele is one which is always shown as a visible characteristic while a recessive allele is only shown if there are two.
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When do genetic diseases occur?
When there is a faulty allele in a single gene.
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What is the likely hood of developing Cystic Fibrosis and what are the symptoms?
A person has a 25% chance of developing Cystic Fibrosis if both parents have the gene as it is recessive. The symptoms are difficulty digesting food and breath due to mucus in the air passage and pancreas.
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What is the likely hood of developing Huntingtons Disease and what are the symptoms?
A person has a 50% chance of developing Huntingtons disease if one parent has the gene as it is dominant. The symptoms are mood changes, tremors and clumsiness.
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What are clones?
Genetically identical organisms.
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Name the three ways clones are produced.
Through Asexual reproduction, artificial cloning and the splitting of an embryo (identical twins).
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Name two ways that plants can reproduce asexually?
Through forming new clones at the tips of stems and producing bulbs which are identical to the plant.
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How does bacteria reproduce asexually?
The parent cell divides to produce two cells which divide on...
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How do greenfly create clones asexually?
They lay eggs which produce identical females.
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If I wanted to artificially clone a sheep, how would I do that?
You place the nucleus of the body cell you want to clone, into the egg cell with its own nucleus removed. It is then stimulated to divide.
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What is genetic testing used for?
Testing for genetic disorders in adults and children before drugs are prescribed. Embryos can also be tested for genetic disorders through pre-implantation or testing the fluid around the fetus.
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What are the possible incorrect results given from genetic testing and why is this?
A genetic test can give a false positive (Told they are healthy when ill) or a false negative result (Told they are ill when healthy) through contamination or misinterpretation of the results.
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What are the ethical issues with genetic testing on embryos?
Tests carried out during pregnancy give a 1% chance of miscarriage. There is also the fact that people think that it's "playing God".
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What are stem cells?
Unspecialised cells that can develop into a different type of cell depending on the instructions given.
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What is the difference between an embryonic and an adult stem cell?
Embryonic stems cells are found in early embryos and can be instructed to turn into any kind of cell, while adult stems are extracted from the bone marrow of adults and can be specialised into most but not all types of cells.
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What can stems cells be used for?
Stems cells can be used to treat blood diseases through a bone marrow transplant and can also mend damaged tissue.
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Other cards in this set

Card 2

Front

Structural proteins such as as collagen found in tendons, bones and cartilage. Functional proteins such as the digestive enzyme amylase.

Back

Name two different kinds of protein.

Card 3

Front

Chromosomes are found in the nucleus of a cell. They are genetic material, 1 per parent per pair, of which there are 23 pairs.

Back

Preview of the back of card 3

Card 4

Front

During fertilisation, the egg and sperm cell each bring 23 chromosomes each with their own version of the same gene (an allele). As the two sex cells fuse, the baby could sperm could have an X (female) or a Y (male) chromosome.

Back

Preview of the back of card 4

Card 5

Front

A Genotype is all the genes an organism has while a Phenotype are the physical characteristics of an organism.

Back

Preview of the back of card 5
View more cards

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