Unit 2 multicellular organisms Flashcards
What is variation
The differences between species
What makes variation discrete
When the measurements fall into distinct groups
What makes variation continuous
When there is a range of values between a maximum and a minimum
What inheritance causes discrete variation
Single gene inheritance
What inheritance causes continuous variation
Polygenic inheritance
What is a gene
A short strand of DNA that codes for a protein
What is the name for different versions of the same gene
Alleles
What does phenotype mean
The physical description e.g. blue eyes
What does genotype mean
The allele description e.g BB
What does homozygous mean
Both alleles are the same e.g. BB or bb
What does heterozygous mean
Both alleles are different e.g. Bb
What are some examples of discrete variation
Eye colour, hair colour, petal colour in plants
What are some examples of continuous variation
Height in humans, leaf length in plants
What does xylem transport
Water in plants
What is the name of the substance that strengthens xylem
Lignin
What does phloem transport in plants
Sugar
What are cells associated with phloem called
Companion cells
What is the structure found in phloem called
Sieve plates
What is the top layer of tissue in a leaf called
The upper epidermis
Where in the leaf does most photosynthesis take place
Palisade mesophyll
What is the spongy mesophyll in leafs
A layer of cells with spaces for gases to diffuse in and out of the plant
What is the bottom layer of the leaf called
The lower epidermis
What is the stomata
Structures on the underside of a leaf that allow water to evaporate out of the plant
What are guard cells
Cells that control opening and closing of the stomata
What is the name for the process of water moving through a plant and it’s evaporation through the stomata
Transpiration
Is the xylem made up of living or dead tissue
Dead
Is the phloem made up of living or dead tissue
Living
What is the direction of transport in the xylem
Upwards only
What is the direction of transport in the phloem
Up and down the plant
What are the organs of a plant
Roots, stem, leaves.
What is the name of the liquid that carries the blood cells
Plasma
What do red blood cells do
Carry oxygen
What if the function of white blood cells
To destroy pathogens
What is a phagocyte
A type of white blood cell that engulfs pathogens
What are pathogens
A microorganism that causes disease
What is the white blood cells that makes antibodies
Lymphocyte
What are the two upper chambers of the heart called
The atriums
What are the ventricles
Lower two chambers of the heart
What does a valve do
Prevents the back flow of blood
What is the largest vein in the body called
The vena cava
What is the largest artery in the body called
The aorta
What is the pulmonary artery
The blood vessel that takes blood to the lungs
What is the pulmonary vein
The blood vessel that takes blood from the lungs to the heart
What are coronary arteries
The blood vessels that supply blood to the heart
What is an artery
A blood vessel that carries blood away from the heart
What is a vein
A blood vessel that takes blood towards the heart
What is a capillary
Tiny blood vessels that allow exchange of materials
What is the structure of the arteries like
They have thick muscular walls
What kind of pressure do arteries carry blood
High pressure
What is the structure of the veins like
It has thinner walls and a wider channel
What pressure do veins carry blood in
Lower pressure
What is the structure of the capillaries
it has very thin walls and a large surface area
What side of the heart pumps deoxygenated blood
The right side
What side of the heart pumps oxygenated blood
The left side
What makes red blood cells specialised
Biconcave in shape, no nucleus, contains haemoglobin
What is absorption
A process where a substance is taken up into a tissue usually crossing a membrane
What is the capillary network
A group of capillaries that deliver blood to a particular tissue
What is the name for the process in which oxygen enters the blood and carbon dioxide leaves the blood
Gas exchange
What are Alveoli
The tiny air sacks found inside the lungs
What is the alveolar wall
The boundary between the air sac and capillaries
What is the organ responsible for the absorption of nutrients
The small intestine
What are villi
The tiny finger like folds in the wall of the small intestine that increase surface area
What is the function of the capillaries in the small intestine
To absorb glucose and amino acids
