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Flashcards in Unit 6 Deck (40)
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Outline the function of genes

Genes code for a particular sequence of amino acids which are put together to make a specific protein


Give one reason why it's important for scientists to have an understanding of the human genome

It allows scientists to identify genes which are linked to different types of diseases. Knowing which genes are linked to inherited diseases could help us develop effective treatments for them


Explain how the DNA bases in a gene code for a specific chain of amino acids

Each sequence of three bases codes for one specific amino acid, so the order of the bases in the Gene decide the amino acids in the chain


Briefly describe the role that non coding DNA plays in protein synthesis

They switch specific genes on or off


Explain how DNA can be used in the synthesis of proteins when it's unable to leave the nucleus

A molecule called mRNA is made by copying the code from the DNA. The mRNA carries the code from the DNA to the site of protein synthesis


Describe the process that takes place at the site of protein synthesis to produce chains of amino acids

Carrier molecules bring the amino acid coded for by the messenger molecule to the site of protein synthesis in the correct order


Explain what happens to a chain of amino acids once it's been assembled

It Folds up into a unique shape, which allows the protein to perform the task it's meant to do


Explain how mutations could lead to a change in the protein being synthesised

Mutations change the sequence of DNA bases in the Gene, and this is the sequence that codes for the specific amino acids in a protein. A change in the amino acids coded could lead to a change in the protein


Suggest one possible effect of a mutation in a gene that codes for a particular enzyme

The shape of the enzymes active site can be changed, meaning that it's substrate May no longer be able to bind to it, so the enzyme will no longer be able to catalyse the reaction


Give four ways in which asexual reproduction is different to sexual reproduction

Only one parent
No fusion of gametes
No genetic variation
Doesntn involved meiosis


Where in the body does meiosis take place

Ovaries and testes


Briefly describe the results of meiosis

4 gametes are produced which each other single set of chromosomes. Each of the gametes genetically different to the others.


Explain why sexual reproduction increases the chance of population surviving

It creates genetic variation in the Offspring which means it is likely that some individuals in the population will have a gene that makes them better adapted to new environment. Individuals with this DNA more likely to survive and breed successfully and passes Gene on to future generations which will allow them to survive in this environment


How can you tell that an allele for a disease is not dominant

If there are carriers


Even if both parents are carriers of cystic fibrosis, it's only a small chance that the baby will get it. Why is this?

Because the allele for cystic fibrosis is recessive so the Offspring must have two copies of the allowed to have this disorder there is only a 1 in 4 chance of this occurring when each parent has a copy of the allele


Suggest three arguments against embryo screening

It implies people with genetic problems that undesirable which could increase Prejudice
Screening is expensive
There could be a point where everyone wants to scream that embryo to pick the most desirable one


Why didn't scientists understand how important mendel's work was at the time

Scientist of his day didn't know about genes DNA and chromosomes


Scientist of his day didn't know about genes DNA and chromosomes

The mutation could lead to a new phenotype. If the environment changes, the new phenotype can make the individual more suited to the new environment. It could then become Common throughout the species relatively quickly by natural selection


What three sources of evidence did Darwin use for his theory of natural selection

His round the world trip
New knowledge of fossils
New knowledge of geology


What explanation is there for new variations in phenotypes

There are genetic variants produced by mutations


How are characteristics passed onto offspring

By Genes


Give five factors which cause a species to become extinct

The environment changes too quickly
A new Predator kills them all
The new disease kills them all
They can't compete with another new species for food
A catastrophic event occurs that kills them all


Why was Darwin's theory of evolution controversial

It went against religious beliefs at the time
He didn't have an explanation for how characteristics are passed on
There was a lack of evidence


What evidence supports Darwin's theory of evolution

Fossil record and discovery of bacteria evolving to become resistant to antibiotics


What is selective breeding

The breeding of organisms are the genes for a particular characteristic staying the population


Some puppies have bred by selective breed. Suggest why the puppies may be more susceptible to genetic defects

Breathing the puppies causes a reduced gene pool. So there's more chance of the puppies inheriting a genetic disease if it's present in the population


What is genetic engineering

The transfer of a gene responsible for a desirable characteristics from one organisms genome into another organisms genome


How are useful genes isolated from organisms DNA

Enzymes are used to isolate the desired gene from the organisms genome


In genetic engineering, the Gene is inserted into the target organisms genome. Explain how this is achieved so that the organism develops with the desired characteristics.

The gene is first inserted into a vector which is then introduced to the target organism and this inserts the Gene into the organism cells so that the organism develops with the desired characteristics


How could genetic engineering be used to treat human diseases

Bacteria can be genetically engineered to produce human insulin
Sheep have been genetically engineered to produce drugs in their mouth that can treat human diseases