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Terms in this set (58)
A lion has 38 chromosomes in each of its body cells
Will the lion have more or less than 38 genes in each of its cell
More because each chromosome contains multiple genes
In which part of the cell is mRNA made?
c) amino acids
Describe mRNA's movements within a cell once it has been made
It moves out of the nucleus to a ribosome in the cytoplasm
Describe what happens to a chain of amino acids once it has been assembled
It folds up into a unique shape
What is meant by the term genetic engineering?
moving genetic information from one organism to another
The host bacterial cell can be replicated many times suggest why this would be done
So that lots of bacteria all containing gene A would be produced
Most of chemical reactions in a cell take place where?
What is the function of the vacuole
Maintaining cell Ph
Which of these cannot diffuse through the cell membrane
d) Carbon dioxide
If an animal cell is surrounded by a very high water concentration it is likely to?
a) Burst, as water will move out of it
b) Burst, as water will move into it
c) Shrink, as water will move out of it
d) Shrink, as water will move into it
What part of the cell is fermentation complete in?
Give one way energy released by respiration is used
cell division, protein synthesis, muscle contraction
If a plant cell is placed in a strong salt solution what will happen?
It will become plasmolyzed due to water loss
Does aerobic respiration require light energy?
Stem cells are specialised/unspecialised cells
Which food molecules are absorbed into the capillaries of the villus?
Amino acids and glucose
What is an ecosystem?
All the organisms living in a particular area and the non-living components (with which they interact)
Explain why a hormone only works on its target cell
the hormone and receptor (proteins) have complementary shapes
State the name given to a section of DNA which codes for a protein.
a community is all the organisms of
a)one species living in a habitat
b) different species living in a habitat
c)one population living in a habitat
d)different ecosystems in a habitat
If there is a rise in DDT concentration as you go up a food chain what is this an example of?
Why may a mutation change the structure of a protein produced by a bacterial cell?
A mutation would change the sequence of DNA bases in a gene which may mean that different amino acids were coded for so the structure of the resulting protein would be different
Explain why animals such as mice show differences in fur colour
Because they have different alleles
Natural selection only occurs when their is a sudden environmental change T/F
Give two selective pressures that animals may face
Competition for resources
What is meant by the term adaptation?
An inherited characteristic that makes an organism more likely to survive in its enviroment
Other than tissue repair give one reason why an organisms cell divide by mitosis
Before mitosis takes place the cell duplicates its DNA
Explain why this is neccesary
So that there will be one copy of the DNA for each new cell produced by mitosis
Where are chromosomes contained in a sperm cell?
In the nucleus
Describe how sexual reproduction contributes to the genetic variation within a species
Sexual reproduction creates genetic variation as each offspring ends up with a different combination of its parents genes
What term is used to describe a characteristic that is determined by several genes?
A woman with blue eyes is expecting a baby.
Explain why it is not certain that the baby will also have blue eyes
The baby will inherit from both its mother and father/ and the combination of alleles will determine its eye colour
What is the role of the part of the nervous system formed by the spinal cord and the brain
It receives information from receptors and coordinates a response
How is information passed along a neuron
What is meant by 'reflex arc'
A reflex arc is the route taken by the information/ impulse/signal in a reflex
Explain why receptor proteins on target cells need to have specific shapes
Need to be complementary to specific hormones
So that the hormones will only affect the target cells
Describe the function of capillaries
To carry blood really close to every cell in the body so that substances can be exchanged with them
What is the function of plasma?
To transport substances around the body
describe how the red blood cells shape helps it to carry out its function
Biconcave = Large surface area for absorbing oxygen
Give two types of pathogens
Describe what happens when a lymphocyte destroys a pathogen
The lymphocyte produces antibodies specific to the type of antigen on the pathogen
The walls of the alveoli are very thin
Explain how this feature aids gas exchange
The gases only have to diffuse a short distance so gas exchange can happen quickly
Explain how the concentration of oxygen in the blood changes as blood flows through the blood capillary from the start to end
The oxygen content at the start is low and increases to the end because oxygen moves from the alveolus into the blood as it flows through the capillary
Describe the net movement of carbon dioxide between respiring cells in the body and the blood in the capillaries
Out of the cells and into the blood
Explain why nutrients from food needs to be absorbed into the blood stream
So that they can be transported to cells all over the body
The villi have a good blood supply. Why is this important for their function
It means that the absorption of nutrients from food molecules into the blood can happen quickly
Give one other way other than having a waxy cuticle which can help reduce water loss from a plant
The stomata can temporarily close
At night the stomata in leaves close
Suggest how this would affect the stage of transpiration that occurs at the roots
Closing the stomata prevents water from evaporating from the leaves so less water would be drawn up through the roots
When measuring the rate of transpiration suggest why having leaves with different total surface areas may have affected the results
Shoots with leaves with a larger total surface area may have more stomata for water to evaporate from than shoots with a smaller total surface area
what is sugar converted into for storage?
give 3 features of Xylem
Hollow, no end walls, lignin
Give 3 features of phloem
sieve plates, sieve tubes, companion cells
describe the way in which DNA strands are linked together
By base pairs
Animal cells in high concentrations ....
Shrink and shrivel