Revision Leaflet- Unit 2 Flashcards
The cells in organs are?
Specialised for their functions.
Stem cells in animals can?
Can divide and have the potential to become different types of cells.
Stem cells are involved in?
Growth and repair
Meristems are where?
Cell division takes place in plants and so are where growth occurs
The cells produced at meristems are?
Non-specialised and have the potential to become many types of plant cell e.g. Xylem, phloem, mesophyll
What is the CNS made up of?
Brain and spinal cord
What does the brain contain?
- cerebrum
- cerebellum
- medulla
What does the cerebrum do?
Stores memories, receives information from our sense organs and controls our actions by sending messages out to the muscles or to glands.
What does the cerebellum control?
Controls co-ordination and balance.
What does the medulla control?
Breathing and heartbeat.
What do the receptors in our sense organs detect?
Stimuli in our surroundings and produce electrical impulses
What do sensory neurons carry?
Electrical impulses to the CNS.
The three types of neurons?
-sensory
-relay
-motor
Make up a reflex arc and bring about fast responses
What is the gap called between each 2 neurons?
Synapse and the electrical impulses are carries across the gap by chemicals.
what do endocrine glands release?
Hormones into the blood stream.
Hormones work on their?
Specific target cells which have receptor proteins they can attach to.
What does the pancreas control?
Our blood glucose level by producing two hormones, insulin and glucagon.
The target cells for insulin and glucagon are in the?
Liver
When is insulin released?
When blood sugar level is high.
In the response to insulin, what does the liver do?
Converts glucose to glycogen for storage.
When is glucagon released?
When blood sugar levels are to low.
In the response to glucagon the liver concerts?
Glycogen back to glucose.
What is diabetes cause by?
Either the pancreas not releasing enough insulin or the liver not responding to it.
Body cells are?
Diploid
Gametes are?
Haploid
Make gametes are?
Sperm and pollen cells
Female gametes are?
Egg cells and ovules
Sperm cells are produced in the?
Testes
Egg cells are produced in?
Ovaries
Pollen is produced in a flowers?
Anther
Ovules are produced in a flowers?
Ovary
What does variation mean?
Differences between organisms, and these differences may be caused by their genes.
What is discrete variation?
The organisms can be places in distinct groups, e.g. Male or female, tongue roller on non-roller
What is continuous variation?
The organism all fit somewhere along a range e.g. Height, handspan
control of a feature by several gene is called?
Polygenic inheritance
Different forms of a gene is called?
Alleles
The appearance of an individual is called the?
Phenotype
The alleles present are called the?
Genotype
What always shows up in a phenotype?
A dominant allele
A recessive allele can be hidden by?
A recessive one
What is homozygous?
Having two identical alleles
What is heterozygous?
Having two different alleles
In a cross, what are the parents called?
The P generation
What is the first generation of offspring?
The F1 generation.
What are the offspring of the F1 generation?
F2 generation
Why do plants require water?
For transporting materials and for photosynthesis
How does water enter a plant?
Through root hairs and passes up through xylem to the leaf.
What are xylem cells?
Xylem cells are dead and are lignified to withstand the pressure changes as water moves through the plant
What are the top and bottom layer of a lead called?
Epidermis
What are the middles layers of a leaf called?
Mesophyll
What does a mesophyll do?
Carry out photosynthesis, so they require water to be brought up to them
What does the lower epidermis contain?
Pores called stomata, and these are opened and closed by the guard cells around them.
What is transpiration?
When water evaporated out through stomata
What does transpiration do?
Speeds up in warm, windy conditions. It is slow in humid conditions.
What do phloem cells do?
Transport sugar through the plant
In mammals what is transported through the blood?
Nutrients, oxygen and carbon dioxide
What are the names of the four chambers of the heart?
Right atrium, right ventricle, left atrium, left ventricle.
What happens to deoxygenated blood?
Returns to the heart in the vena cava and enters the right atrium.
where does blood pass?
To the right ventricle and leaves for the lungs along the two pulmonary arteries.
What happens with oxygenated blood?
Returns from the left atrium to the left ventricle and leaves for the body along the aorta
What do the valves in the heart help?
To prevent backflow of blood.
Where does the heart muscle get food and oxygen from?
From the blood in its corniest arteries
What do arteries do?
Carey blood which has recently been pumped by the heart and so is under high pressure.
What do arteries have?
Thick, muscular walls with a narrow central channel.
What do veins do?
Carry blood returning to the heart and this blood is under low pressure.
What do veins have?
Thinner walls with a wide channel
What do capillaries do?
Form networks in organs and tissues, forming a link between the ends of the arteries and the veins.
What do capillaries have?
Thin walls and have a large surface area, allowing exchange of materials ( oxygen and food to pass out of blood to cells, carbon dioxide and waste to pass from cells into blood)
What do red blood cells contain?
Haemoglobin and are specialised to carry oxygen in the form of oxyhemoglobin.
How are our airways kept open?
By rings of cartilage
Where is the aveoli?
In the lungs
What happens in the aveoli?
Oxygen passes into the blood and carbon dioxide passes out
What does alveoli have?
Thin walls, a large surface area, a good blood supple allowing more efficient diffusion of gases
What does mucus trap?
Dirt and microorganisms
What does cilia do?
Moves dirt and microorganisms away from the lungs
How is food moved through the digestive system?
By peristalsis
How is digested food absorbed?
From small intestine into the blood across the villi.
What is a villus?
Is found in the small intestine, has thin walls, a large surface area and a good blood supply.
What does the villus absorb into the blood?
Glucose and amino acid
How are fatty acids and glycerol absorbed?
Into the lacteal.
What are bad choices we make about our lifestyle?
High fat or high salt diet, lack of excersising, use or tobacco or alcohol, or high stress levels may increase the chances of fatty deposits in blood vessels, blood clots, heart attacks, strokes, diabetes and stress
What does a lack of iron mean?
Haemoglobin cannot be made and can lead to heavy metals, radiation and pollution.
What plays a big part on human conditions?
Heredity (our genes)
What are multicellular organisms?
They have more than one cell type and are made up of tissues and organs.
