Biology 4, 5, 6 Questions Flashcards
What do A C G and T stand for?
Adenine, Cytosine, Guanine and Thymine
Who were the first two scientists who worked out the structure of DNA?
Watson and Crick
How do plants use glucose to make protein?
Glucose is combined with nitrate ions from the soil to make amino acids, which are made into proteins
Why are insoluble substances (like starch)used for storage in plants?
- They don’t affect water concentration in cells
- They dissolve in water, so they cant move away from storage areas in solution.
What is the definition of ENVIRONMENT?
All the conditions that surround a living organism
What is the definition of HABITAT?
The place where an organism lives
What is the definition of POPULATION?
All the members of a single species that live in a habitat.
What is the definition of COMMUNITY?
All the populations of different organisms that live together in a habitat
What is the definition of ECOSYSTEM?
A community and the habitat in which it lives
How do you estimate population size?
Number in 1st sample x number in 2nd sample / number in 2nd sample previously marked
What other substances can glucose be used for or stored for?
- For respiration to release energy
- Stored in seeds and turned into lipids
- Making proteins for growth and repair
- Turned to cellulose for making cell walls
- Stored as starch when photosynthesis is not happening (at night)
What did Priestley’s experiments show?
Plants restore something to the air that burning and breathing take out. This substance is oxygen.
What did Van Helmont’s experiments show?
The tree must have gained mass from another source. Plants also gain mass using CO2 from the air and not just from taking in minerals from the soil.
What three limiting factors control the rate of photosynthesis?
Light intensity, carbon dioxide levels and temperature
What is diffusion and where does it happen?
The net movement of particles from an area of high concentrations to an area of low.
This happens in liquids and gases.
What does the rate of diffusion depend on?
The distance, the concentration of the particles and the surface area.
What are the 6 different ways of preserving food?
Canning, Cooling, Freezing, Drying, Adding Salt and Sugar and Adding Vinegar
What is Hydroponics?
Growing plants in mineral solutions without the need for soil
What is Biological Control?
The use of living organisms to control pests
What is transpiration?
The loss of water from a plant caused by evaporation and diffusion in the leaves.
What are the benefits of the transpiration system?
- It keeps the plant cool
- The plant has a constant supply of water for photosynthesis
- Water creates turgor pressure in the plant cells, which give it support and stops it from wilting.
What is Xylem?
They take water and minerals from the roots up the shoot to the leaves in the transpiration stream.
What is a Phloem tube?
They transport food substances up and down the stem to growing and supporting tissues.
What is osmosis?
The net movement of water particles across a semi permeable membrane from a region of high concentration to a low.
What four minerals do plants need?
Nitrates (for making amino acids and proteins for cell growth), Phosphates (for respiration and growth), Potassium (for photosynthesis and respiration) and Magnesium ( for making chlorophyll)
What do the bases pair up with?
A pairs with T and C pairs with G
How does the transpiration rate increase?
When there is:
- an increase in light intensity
- increase in temperature
- increase in air movement
- decrease in air humidity
What are ethical reasons why intensive farming is bad.
- Pesticides can disturb food chains
- Removing hedges to make bigger fields destroys habitats
- Careless use of pesticides can cause water pollution
- Some people think that keeping animals in small spaces is cruel
What are the disadvantages of hydroponics?
Lots of fertilisers need to be added and there is no soil to anchor and support the plants
What are the advantages of hydroponics?
- You can control mineral levels and diseases more efficiently
How are leaves adapted to diffusion?
- Large surface area
- Thin, making carbon dioxide and water vapour diffuse a short distance
- The stomata lets gases in and out and allow water to escape.
What is the order in decreasing complexity, starting from the nucleus?
Nucleus - Chromosome - Gene - Base
What are the advantages of an internal skeleton?
- It can easily grow with the body
- It’s easy to attach muscles to it
- It’s more flexible than an external skeleton
- it gives the body support and a framework
Why are long bones hollow?
It makes them lighter and stronger than a solid bone.
What is the process called where your cartilage turns into bone?
Ossification
What is osteroporosis and how can it be treated?
A condition where calcium is lost in bones, causing it to become more brittle and more likely to break. It can be treated with calcium supplements.
What is meant by antagonistic pairs?
When one muscle contracts, the other relaxes to make movement in the arm
What does the synovial membrane in a joint do?
It lubricates the joints, allowing them to move easily
Why is keeping the blood at high pressure a good thing in a double circulatory system?
It allows materials to be transported around the body quicker
What happens in the cardiac cycle?
- Blood flows through the two atria
- The atria contract, pushing blood through the ventricles
- The ventricles contract, forcing the blood into the aorta and the pulmonary artery
- The blood flows along the arteries then the cycle starts again.
What are the two pacemakers in the heart and what do they do?
The Sino-Atrial Node (SAN) and the Atrio-Ventricular Node (AVN). The SAN stimulates the atria to contract and the AVN simulates the ventricles to contract. This process ensures that the atria always contracts before the ventricles.
Which cardiogram shows the electrical activity of the heart?
Electrocardiograms
What can echocardiograms show?
An ultrasound scan of the heart can show:
- An enlarged heart (indicates heart failure)
- Decreased pumping activity (cardiomyopathy)
- Valve function (torn, infected or scarred)
What is a ‘hole in the heart’?
A gap in either the two atria or ventricles. It allows oxygenated and deoxygenated blood to mix, which reduces the amount of oxygen in the blood being pumped around the body.
What happens to the blood if a valve is damaged?
It can cause the valve to not open properly, causing high blood pressure. It can also make blood flow both directions rather than forwards, so blood does not circulate as efficiently.
What is Coronary Heart Disease?
When the coronary arteries supplying blood to the heart muscle gets blocked by fatty deposits.
Why and how does your blood clot?
WHY:
To prevent too much bleeding
HOW:
A mesh of protein fibres (fibrin fibres) ‘plug’ the damaged area. They are formed by chemical reactions that take place when the platelets are exposed to damaged blood vessels.
What is Haemophilia?
A genetic condition where the blood doesn’t clot as easily because a clotting factor can’t be made by the body.
What happened when an antigen and an antibody of the same letter meet?
Agglutination occurs. This is when the blood clumps together.
How is the alveoli adapted to gaseous exchange?
- Large surface area to increase the rate of diffusion
- Moist surface to help oxygen and carbon dioxide dissolve
- Permeable surface to help gases exchange easily
- Thin lining (1 cell thick) so that gases don’t have to diffuse very far
- Good blood supply
What does Carbohydrase break down and where is it active?
Big Carbohydrates into simple sugars like glucose.
The are active in the: mouth and small intestine
What does Protease break down and where is it active?
Proteins into amino acids.
They are active in: the stomach and small intestine
What does Lipase break down and where are they active?
Fats to fatty acids and glycerol
They are active in the small intestine
What does the FSH cause?
An egg to develop in one of the ovaries
What does Oestrogen cause?
The lining of the uterus to repair and thicken
What does LH cause?
The stimulation of egg release.
What does Progesterone cause?
The maintenance of the uterus lining
What are the four main shapes of bacteria?
Spherical, Rod, Spiral and Curved Rods
Bacteria reproduce by Binary Fission. What is this?
One cell splits into two new cells
In a flagellate bacterial cell, what are the flagellum, cell wall and bacterial DNA for?
Flagellum - For movement.
Cell Wall - To maintain shape and to stop the cell from bursting.
Bacterial DNA - To control the cell’s activities and replication.
What is biomass?
Living or recently dead organic material
What are the advantages of biomass?
- Plants grow to make biogas photosynthesise, which removes carbon dioxide
- Biogas is a cleaner fuel than diesel or petrol
What are the disadvantages of biofuels?
- Biogas doesn’t contain as much energy as the same volume of natural gas
- Large areas of land are sometimes cleared of vegetation
- Habitat loss
- Extinction of species
