B2.7 Flashcards
What is the definition of gamete?
Sex cell made in the reproductive organs e.g pollen, egg, sperm
What is the definition of homozygous?
When both of the alleles are the same
What is the definition of heterozygous?
When the two alleles are different
What is the definition of phenotype?
The physical appearance regarding a characteristic
What is the definition of genotype?
The genetic makeup of an individual regarding a particular characteristic
(The combination of alleles for a characteristic)
What is the definition of dominant?
Allele controls the characteristic if present on only one chromosome
What is the definition of recessive?
Allele controls the characteristic if present on both chromosomes
What are chromosomes made up of?
Large molecules of DNA
Where are chromosomes found?
In the nucleus of the body cells in pairs
What structure does DNA have?
A double helix structure
What’s a gene?
A small section of DNA
What are some characteristics, such as appearance, controlled by?
A single gene called monohybrid inheritance
What is an allele?
A form of the gene, which in Mendel’s experiment, controlled whether the pea was smooth or wrinkly
How many cells does mitosis produce?
2 cells for every 1 (1 set of division)
How many cells does meiosis produce?
4 cells for every 1 (2 sets of division)
What type of cell division do sex cells do?
Meiosis
What type of cell division do all body cells except sex cells do?
Mitosis
How many chromosomes does a cell divided through mitosis have?
46 chromosomes
How many chromosomes does a cell divided through meiosis have?
23 chromosomes
A combination of XX chromosomes will produce what gender baby?
Female
A combination of XY chromosomes will produce what gender baby?
Male
Where can stem cells be taken from?
~ The embryo
~ The umbilical chord
What are cells produced from mitosis used for?
~ Growth
~ Repair
~ Asexual reproduction
What are gametes?
Sex cells
What is a zygote?
A ball of cells containing the egg and sperm
What method of division does a zygote use?
Mitosis
What are social thoughts on testing on embryonic stem cells?
~ Could save lives
~ Could cure diseases
~ Save costs
What are ethical thoughts on testing on embryonic stem cells?
~ like killing humans
~ no right to interfere with lives (religious views)
Why was Mendel’s work not discovered until after his death?
~ He was a monk
~ His work hadn’t been widely published
What do genes carry?
The codes to build proteins
How many types of bases are there on DNA strands?
4 types
How many bases code for one type of amino acids?
3 bases (triplets) next to each other
How many types of amino acids are there?
About 20
What does the combination of the different amino acids make?
A protein
What did Mendel do?
He cross-fertilised tall and short pea plants to see whether the peas produced contained the qualities of their parents
What did Mendel find?
That there was a 3:1 ratio of tall to small pea plants, so he knew that there was a dominating factor
How can stem cells be removed from adults?
From bone marrow
Why is it seen as unethical to test on embryonic stem cells?
~ The embryo will be destroyed
~ People believe that the cells make up a human immediately after fertilisation
What is there a risk of with embryonic stem cells?
Cancer
Adult stem cells have been used to treat Leukaemia for how many years?
40
What can adult stem cells treat?
~ Patients with nervous system disorders
~ Leukaemia
Is cystic fibrosis caused by a dominant or recessive allele?
Recessive
Is polydactyl caused by a dominant or recessive allele?
Dominant
How many parents are needed to pass on cystic fibrosis?
2
How many parents are needed to pass on polydactyl?
1
What is the main symptom of cystic fibrosis?
A disorder of the cell membranes
What is cystic fibrosis a disorder of?
Cell membranes
What are the main symptoms of polydactyl?
Having extra fingers and toes
What alleles do sufferers of cystic fibrosis have?
cc
What alleles do sufferers of polydactyl have?
PP or Pp
Can you be a carrier of cystic fibrosis?
Yes, and you can have no symptoms
Your alleles would be Cc
Can you be a carrier of polydactyl?
No
What did Mendel refer to genes as?
Inherited factors
What do identical twins have the same of and why?
~ DNA
~ because they’re made from the same sperm and egg cells
Why might DNA fingerprinting be used?
~ To identify mothers and fathers of babies
~ To identify criminals
What do embryonic stem cells do?
Divide and specialise to become all the cells in the fully formed body
What do adult stem cells do?
Divide to replace dead or damaged cells
What are the two alleles of polydactyl?
Affected and unaffected
What does cystic fibrosis affect?
~ Cell membranes
~ Pancreas (digestion of food)
~ Lungs (breathing, infections)
How can you know if an embryo has certain conditions?
Embryo screening
What are advantages of embryo screening?
~ Save lives
~ Eradicate diseases
~ Improve quality of life
What are ethical thoughts on embryo screening?
~ Killing humans
~ Designer babies
~ Choosing gender
What are economical thoughts on embryonic screening?
~ Save costs if children are born without conditions
~ Medical treatment will be reduced
~ Less drugs will need to be developed
Many plant cells retain the ability to do what?
Differentiate throughout life
What are stem cells?
Cells from human embryos and adult bone marrow
What can stem cells be used to do?
Differentiate into many different types of cells e.g. Nerve cells
Human stem cells have the ability to do what?
Develop into any kind of human cell
Offspring produced by asexual reproduction contain the same what as their parents?
Same alleles
What are 2 inherited disorders?
~ Polydactyly
~ Cystic fibrosis
