N4 Unit 2 Part B Flashcards
What is variation?
The differences between members of the same species
What is discrete variation?
Variation which falls into distinct groups e.g. blood type.
What is continuous variation?
Variation which has a range of values e.g. height.
In which cell structure is the genetic information found?
Nucleus
What percentage of their DNA does a child inherit from each parent?
50%
What does polygenic mean?
A trait which is controlled by many genes
What name is given to the different forms of a gene?
Allele
How many copies of every gene does a diploid organism have?
Define the term recessive.
Recessive alleles only show up in the appearance of an organism if they are paired with another recessive allele.
Define the term dominant.
Dominant alleles always show up in the appearance of the organism even if there is only one copy present in the gene pair.
Define the term phenotype.
Phenotype describes the appearance of an organism.
Define the term genotype.
The genotype of an organism tells us which forms of each gene (alleles) are present.
What is germination?
The process whereby a seed starts to grow.
What factors are required for germination?
Water, oxygen and a suitable temperature.
What is an annual plant?
Annual plants go through their whole life cycle in a single year.
What is a perennial plant?
Perennial plants do not die but grow again next year.
What are mammals?
Animals which are warm-blooded with a backbone and produce milk to feed its young.
What factors do humans need to grow and develop properly?
Water, a balanced diet, vitamins and minerals
What is homeostasis?
Keeping conditions in the body at a constant level.
Why is it important to maintain a stable body temperature?
To ensure the chemical reactions in the body can take place at the right speed.
Name two conditions in the body which need to be kept constant.
Blood glucose concentration and temperature
Which organ detects changes in body temperature?
Brain
Which organ acts as the effector to maintain your temperature?
Skin
What is vasodilation?
The arterioles at the surface of the skin dilate to allow heat to be lost by radiation.
Give body responses to an increase in temperature?
Vasodilation, increased sweating and hairs lie flat.
What is vasoconstriction?
The arterioles at the surface of the skin constrict to reduce heat loss by radiation.
Give body responses to a decrease in temperature?
Vasoconstriction, shivering and hairs stand on end.
How does sweating aid heat loss?
As the sweat evaporates heat is lost from the body.
How is glucose stored in the body?
As glycogen
Where is glycogen stored?
In the liver
Which organ releases insulin and glucagon?
Pancreas
Which hormone is released when blood glucose concentration increases?
Insulin
What is the role of insulin?
Causes the liver to turn glucose into glycogen
Which hormone is released when blood glucose concentration decreases?
Glucagon
Which is the role of glucagon?
Causes the liver to turn glycogen into glucose
