B1 Flashcards
The instructions to control how an organisms develop an function are called what and are found where?
They are called genes and they are found in the nucleus of a cell
Genes are instructions for a cell that describe what?
How to make proteins
What are the two types of enzymes an give an example for each?
Structural ie collagen
Functional ie enzymes such as amylase
What is a gene?
A section of a very long DNA molecule
What is a chromosomes?
Chromosomes are long,coiled molecules of DNA
Give examples of features determined by environmental factors genetic factors and a combination of both?
Scars. Dimples, Weight
Which two factors determine the characteristics of an organism?
Environmental factors and genetic factors
Give an example of a characteristic that is several working together?
Eye colour
In terms of chromosomes describe the difference between body cells and sex cells?
Body cells contain pairs of chromosomes,(23 pars, 46 chromosomes) but sex cells contain only one chromosome from each pair (23 single chromosomes)
What is the name for different versions of the same gene?
Alleles
How many alleles does an individual usually have for each gene?
Two
What are terms used for the same alleles and for different alleles of the same gene?
Homozygous and Heterozygous
Why do offspring not look identical to one parent?
Because genes from different parents come together to produce variation in their offspring
Why do offspring have some similarities to their parents?
Because genes from their parents combine in fertilisation of the egg cell
Why don’t all off spring look identical to their brothers and sisters?
They inherit a different combination of alleles from their mother and father.
If an individual has one or both dominant alleles will they show the associated dominant characteristics?
Yes.
If an individual has one recessive alleles, will they show the associated recessive characteristics?
No.
If an individual has both recessive alleles, will they show the associated recessive characteristics?
Yes
Recall the sex chromosomes for males and females?
Males are XY and females are XX
Where is the sex-determining gene located?
On the Y chromosome.
What does the sex-determining gene on the Y chromosome trigger?
The development of the testes
What does an absence of a Y chromosomes trigger?
the development of ovaries
What does the term genotype mean?
It is used to describe the genetic make up of an individual (the gene that someone has )
What does phenotype mean?
It is used to describe the observable characteristics that an individual has
Give two example of a faulty allele of a single gene.
Cystic fibrosis and Huntington’s diease
What disease is caused by a faulty dominant allele?
Huntington dieases
What diseases is caused by a faulty recessive alelle?
Cystic fibrosis
Give three symptoms of Huntington’s diease
Tremors,
Clumsiness,
Memory loss,
Inability to concentrate
Give three symptoms of Cystic fibrosis
Thick mucus,
Difficulty breathing
Chest infections
Difficulty in digesting foods
Can someone be a carrier of a dominant disorder? Why?
No, Because if someone has one allele they will show the characteristics of the faulty disorder.
Can someone be a carrier of the recessive gene? Why?
Yes, Because if they have one recessive allele they will not show the symptoms of the disease but they could pass it on to their children
List five considerations that must be made when testing adults and foetuses for alleles that cause genetic disorder
- Risk of miscarriage as a result of cell sampling
- False positive and negatives
- Whether or not to have children as a result of the tests
- Whether or not to have the pregnancy terminated
- Whether other members of the family should be informed
Describe two implications of testing embryos for embryo selection prior to implantations
- The possibility of designer babies
2. some embryos will be destroyed
Describe the implications of the use of genetic testing by employers and insurance companies
- People may lose their jobs
- Employers may be able to cater for the person needs better
- Insurance may be hard to get
- Insurance may be expensive
- People may not get job
What is a clone?
An individual with identical genes with another
Name two organisms that produces asexually to form clones
Bacteria and plants
What factor can contribute to differences between clones?
Environmental factors
How can a clone in an animal form naturally?
When cells of an embryo seperate to form identical twins
How can a clone of an animal be made artificially?
By using the nucleus of an adult body cell and transferring it to an empty unfertilised cell and implanting it into a female’s uterus
Describe an adult stem cell
An unspecialised cell that can develop in many, but not all, types of cell.
Describe an embryonic stem cell
It is unspecialised cell that can develop into any type of cell
Why do adult and embryonic stem cells have the potential to treat diseases?
Because they are unspecialised stem cells they may be treated so they can divide into tissue organs and that can replace or change the functionality of existing tissues and organs within a organisnms
In multicellular organisms, when do the majority of cells become specialised?
During the early development (embryo- foetus)
