Unit 6 Flashcards
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
Suggest two ways a plants genes can be altered to increase his yield
To make them resistant to herbicides and resistant to disease or insects
Give one concern people have about GM crops
Reduce biodiversity
Transplanted genes can get out into the natural environment
Describe the process of animal cell cloning
An unfertilized egg egg cell with have its nucleus removed. An adult body cell with them be taken from the pig being cloned and its nucleus would be removed. The nucleus from the adult body cell would then be inserted into the empty egg cell. The Egg cell would then be stimulated by an electric shock to divide like a normal embryo. When embryo is then a ball of cells, it would be implanted into the womb of an adult female pig, it would develop into a genetically identical copy of the Prize winning Pig.
Describe two ways that fossils are formed
Gradual replacement of parts of an organism by minerals
From the present cast and impression of things like footprints
Scientists unable to use the fossil record as conclusive evidence to disprove theories about how life Began on Earth. Explain why this is the case.
Many early life forms with soft bodies and decayed completely without forming fossils. Fossils that did for may have been destroyed by geological activity. This means that the fossil record is incomplete.
Give two examples of antibiotics being prescribed inappropriately
Non serious condition descriptions
Being subscribed for viral illnesses
Non serious condition descriptions
Being subscribed for viral illnesses
Explain how antibiotic resistant strains of bacteria develop and spread
Bacteria develop random mutations in the DNA, some of which lead to the bacteria becoming less affected by antibiotics. These bacteria are better able to survive and reproduce in host undergoing antibiotic treatment, meaning the Gene becomes more common in the population, forming antibiotic resistant strains. As there is no effective treatment for these drains, it can spread very easily between individuals
What evidence do scientists use to prepare evolutionary trees
The fossil record and current classification data
Which of the domains includes primitive bacteria often found in extreme environments
Archaea
Who proposed the three domain system
Carl Woese
