Biology Core 1 2 3 Flashcards
(26 cards)
True or false-in humans, chromosomes are usually found in groups of four?
False.
Where are chromosomes found within a cell?
In the genetic material in the nucleus.
What are alleles?
Different versions of the same gene.
What does the word genotype mean?
Genotype is all the characteristics a person has.
What does the word phenotype mean?
Phenotype is all the characteristics a person shows.
Is a persons wight determined by their genes, the environment or a combination of both?
A combination of both.
Name the two sex cells.
Sperm and egg.
How many chromosomes are found in sex cells?
23 pairs each.
Why do children look a bit like both parents but not identical to either?
Because they’ve only got half the amount of alleles from each parent not all of them.
What’s the difference between homozygous and heterozygous?
Homozygous is where you have two same alleles and heterozygous means when you have two different alleles.
What sex chromosomes do human males have?
XX
What’s the allele for cystic fibrosis recessive or dominant?
Recessive.
What are the symptoms for cystic fibrosis?
Thick sticky mucus in the air passages and breathing difficulty.
What are the symptoms of Huntington’s disease?
Tremors and clumsiness.
What’s the chance of a child inheriting Huntington’s disease if one of their parents have one copy of the faulty allele?
There’s 50% chance of the child inheriting the faulty allele.
During IVF treatment what is the process of testing embryos to see if they have a genetic disorder called?
Pre-implantation genetic diagnosis.
Other than testing embryos during IVF, give one other use of genetic testing.
Children and adults can be tested before certain drugs are prescribed to them e.g. if the drug will be an effective treatment or if the person will have an adverse reaction to it.
Describe three issues surrounding genetic testing.
Insurance companies might not give life insurance to people with the wrong alleles, tests carried out when a lady’s in pregnancy aren’t 100% safe and is it correct for a person who’s at risk of passing on a genetic condition to have children.
What’s the definition of clone?
Clones are genetically identical organisms.
How does bacteria reproduce asexually?
It simply divides into two meaning it can multiply very quickly.
How does a few plants reproduce asexually?
A few plants produce underground fleshy structures called bulbs.
How does a few animals reproduce asexually?
Female greenfly don’t need to mate-they can just lay eggs.
How are identical twins formed?
The embryo splits into two and the two embryos begin to develop. The two embryos are genetically identical meaning two identical twins are born.
What are stem cells?
Stem cells are unspecialised cells meaning they can develop into different kinds of cells depending on what instructions.
