B6 - Inheritance, Variation and Evolution. Flashcards Preview

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Flashcards in B6 - Inheritance, Variation and Evolution. Deck (17):

What is DNA? 

Deoxyribonucleic acid. It's the chemical that all of the genetic material is made up from. 


What are chromosomes? 

They are really long molecules of DNA, coming in pairs.


What is a gene? 

A gene is a small section of DNA found on a chromosome - they contain instructions for our personal human characteristics. 


What is an organism's genome? 

An entire set of genetic material in an organism. 


What is the gametes produced by the mother and father? 

Sperm and an egg. 


What is sexual reproduction? 

Sexual reproduction involves the fusion of male and female gametes, there is two parents, the offspring contain a mixture of their parents' genes. 


What is asexual reproduction? 

Theres only one parent so the offspring are genetically identical to that parent. 


What does each gene code for? 

It tells the cells to make a particular sequence of amino acids which are put together to make a specific protein. 


What is meiosis? 

Meiosis is the type of cell division of gametes in humans. 


What are alleles? 

All genes exist in different versions called alleles (which are represented in letters in the diagram.) 


What does it mean if someone is heterozygous for a gene? 

If an organism's two alleles for a gene are different, then it's heterozygous. 


Give two reasons for and against embryo screening. 

For; It will help stop people suffering, treating disorders costs the government alot of money.

Against; It implies that people with genetic problems are 'undesireable', it's expensive.  


What is variation? 

Differences within a species. 


What are mutations? 

Changes to the genome, a rare, random change in an organism's DNA that can be inherited. 


What is selective breeding? 

Humans artificially select the plants or animals that are going to breed for genes that are useful or attractive who remain in the population. 


What is the basic idea of genetic engineering? 

To transfer a gene responsible for a desirable characteristic from one geonome to another. 


Give two ways that fossils can be formed? 

Casting - fossils can be buried in material like clay, the clay later harderns, leaving a cast of the organism. 

Gradual replacement - things like teeth, shells and bones don't decay, they are replaced by minerals then later digged up.