Unit 1
Name the basic units of life
Cells
Name two types of molecule present in the cell membrane
Phospholipids and Proteins
State what makes up the CNS
Brain and Spinal Cord
Name the 4 chambers of the heart
Left, Right atrium and ventricles
What is the difference between a biotic and abiotic factor
Abiotic factors are the non-living things of an ecosystem. e.g. temperature
Biotic factors comprise of the living things of an ecosystem. e.g. predation
Give the function on each of the following structures:
- Chloroplasts
- Mitochondrion
Chloroplasts are the sites for photosynthesis and where the photosynthetic pigment chlorophyll captures the energy from sunlight, converts it, and stores it in the energy-storage molecules ATP, while freeing oxygen from water in plant and algal cells.
Mitochondria - the primary function of which is to generate large quantities of energy in the form of adenosine triphosphate (ATP).
Define the terms diffusion and osmosis
Diffusion - Movement of molecules from a region of high concentration to a region of low concentration until the concentration gradient becomes equal.
Osmosis - Movement of water molecules from a region of high water concentration to a region of low water concentration across a membrane.
Where are sperm produced
Testes
Stomata are mainly found where on a leaf?
Lower side
Name a technique which could be used to estimate the total number of dandelion plants in a large patch of grass
Use a quadrat
Name 4 structural features that a typical plant cell and a typical animal cell have in common?
Cell membrane, cytoplasm, mitochondrion and nucleus
Note down the Respiration equation
Glucose + oxygen → carbon dioxide + water + energy
State the meaning of the terms genotype and phenotype
Genotype, the genetic constitution of an organism.
A phenotype is the physical expression of DNA.
Construct a table to contrast the xylem and phloem
xylem - transports water and minerals upwards, lignin to strengthen
phloem - transports sugars, companion cellsName the three isolation barriers that exist
Geographical, ecological and Reproductive
Express 1 millimetre in micrometres
1000um
Which enzymes breaks Starch into Maltose
Amylase
What is meant by the term transpiration
Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers.
Explain how the internal structure of a villus is suited to the transport of digested food
Well suited because of its structure. It is very long and its internal surface is folded and bears tiny finger-like projections called villi. As a result the small intestine presents a large absorbing surface area to the digested food.
Explain the difference between the terms species and speciation
A species is a group of organisms that can create new individuals that are fertile, and thus, can produce even more offspring.
Speciation is the process by which new species form.
Name 4 components of a bacterium cell
Cell wall, cell membrane, plasmid, circular chromosome
What is meant by the term genetic engineering
The transfer of pieces of chromosomes containing sections of DNA from one organism such as a human being to another organism such as a bacterium.
Describe the mechanism of peristalsis
Peristalsis is the involuntary movements of the circular muscles, primarily in the digestive tract that occur in progressive wavelike contractions allowing the passage of food.
Explain what is meant by the terms discrete and continuous variation
Discrete - if it can be used to divide up the member of a species into two or more distinct groups.
Continuous - varies amongst the members of a species in a smooth continuous way from one extreme to the other and does not fall into distinct groups
Describe the process of natural selection
The process by which forms of life having traits that better enable them to adapt to specific environmental pressures, as predators, changes in climate, or competition for food or mates, will tend to survive and reproduce in greater numbers than others of their kind, thus ensuring the perpetuation of those favourable traits in succeeding generations.