Biology and physics assessment Flashcards
What are proteins?
Proteins are the major structural material of animal tissue.
How are proteins formed?
By joining thousands of amino acid molecules together.
How are proteins formed in a condensation reaction?
Formed in a condensation reaction when amino acid molecules join together and a water molecule is removed
Essential amino acids
The body can’t always make amino acids which are required to build up protein in the body.
Breaking down proteins
protein molecules are broken down by hydrolysis
Fibrous proteins
major structural material of animal tissue and are found in animal hair, nails and muscle.
Globular proteins
Are involved in the regulation of life processes, they have their spiral chains which are folded into spherical shapes and are generally soluble in water.
Independent variable
Altered or changed during an experiment
Dependent variable
Being tested or measured during an experiment
Controlled variable
A variable which stays the same throughout the experiment
Example of an independent variable
temperature
Example of a dependent variable
Time taken for starch to be digested
Example of a controlled variable
pH, enzyme concentration and volume of enzyme
Testing for proteins
Starch is detected by using the iodine solution
Iodine solution
When starch is present, solution turns blue-black
Reducing sugars detected using…
Benedict’s solution
Lipids are detected by…
the emulsion test
How food’s broken down
Broken down into smaller pieces in the mouth by chewing- mechanical digestion
Ingestion
Food enters the digestive system through the mouth
Digestive enzymes
Digestion is the break down of large insoluble food molecules into smaller ones
Chemical digestion…
chemical digestion involves enzymes. These are proteins that function as biological catalysts.
Protease catalysts
The breakdown of proteins in amino acids in the stomach and small intestine
lipases catalysts
the breakdown of fats and oils into fatty acids and glycerol in the small intestine
amylase catalysts
Causes the breakdown of starch into maltose in the mouth and small intestine
maltease catalysts
the breakdown of Maltose into glucose in the small intestine
photosynthesis- word
carbon dioxide+water—-glucose+oxygen
(light)
symbol equation- photosynthesis
6co2+6H20—-C6 H12 O6+6CO2
Which energy?
Light
Light energy is absorbed by a green pigment called…
chlorophyll
Where is chlorophyll in the plant?
Located in chloroplasts in plant cells, paticulary in the palisade and spongy mesophyll cells
Where does carbon dioxide enter the leaves?
Through the stomata
Water enters the plants…
through the roots and is transported to the leaves in the xylem
Biosynthesis
some of the glucose formed for photosynthesis is used for respiration.
ways to measure the rate of photosynthesis
the rate of oxygen output
the rate of carbon dioxide uptake
the rate of carbohydrate production
factors that can affect the rate of photsynthesis
light intensity
carbon dioxide concentration
temperature
The amount of chlorophyll can also effect the rate of photosynthesis
plants in lighting conditions unfavourable for photosynthesis synthesise more chlorophyll, to absorb the light required
the effects of some plant diseases affect the amount of chlorophyll, and therefore the ability of a plant to photosynthesise
Light intensity-
without enough light a plant can’t photosynthesis quickly,
light intensity graph
increasing the light intensity, increases the rate of photosynthesis, until some other factor- a limiting factor becomes in short supply. The graph then levels off at a constant rate
Carbon dioxide
if the concentration of carbon dioxide is increased so will the rate of photosynthesis
carbon dioxide graph
The graph increases until it gets to a certain point where factors become limiting
Temperature
At low temperatures the rate of photosynthesis is limited by the number of molecular collisions between enzymes and substrates
Temperature graph
Photosynthesis works better when the temperature is higher but when it gets to 40 degrees the enzymes begin to denature.
Water affecting photosynthesis
In the UK, water is often the main limiting factor for photosynthesis.
light affecting photosynthesis
light intensity fluctuates during the day and is affected by the weather.
Carbon dioxide affecting photosynthesis
Levels of carbon dioxide are rising because of the amount of greenhouse gas emmisions
required practical- photosynthesis
a lamp with an led bulb is set up at different distances from the plant in the beaker of water
method for required practical- photosynthesis
Set up a boiling tube containing 45 cm3 of sodium hydrogencarbonate solution (1%). Allow the tube to stand for a few minutes and shake to disperse any air bubbles that might form.
Cut a piece of the pondweed, Cabomba. The pondweed should be 8 cm long.
Use forcepts to place the pondweed in the boiling tube carefully. Make sure that you don’t damage the pondweed, or cause the liquid to overflow.
Position the boiling tube so that the pondweed is 10 cm away from the light source. Allow the boiling tube to stand for five minutes. Count the number of bubbles emerging from the cut end of the stems in one minute. Repeat the count five times and record your results.
Calculate the average number of bubbles produced per minute. Repeat the experiment at different distances away from the light source.
Variables
variables for required practical photosynthesis
independent variable- distance from the light source/ light intensity
dependent variable for photosynthesis
the number of bubbles produced per minute
control variables
concentration of sodium hydrogen carbonate solution, temperature, using the same plant piece everytime
Charge equation
current x time (Q=IT)
Charge is measured in…
coulombs (C)
Current is measured in…
Amphs (A)
Time is measured in…
Seconds (S)
Voltage is…
The same
What is voltage also referred to
Potential difference
What does it need to do, to make it flow more easily?
The more components, the more potential difference
What is resistance?
The measure of how difficult a component is to get past
To get past a resister what is needed?
More energy is needed
The equation for resistance
Resistance=voltage divided by current
V divided by A
Current…
is the same
What happens in resistance in a series circuit?
All the resistors in the series circuit add up
To calculate resistance in a series circuit…
It is voltage divided by resistance
What happens to resistance when temperature increases?
Resistance decreases
Potential difference is…
The difference between the volts carried before and after the component. So the amount of energy transferred by the electrical component per unit of charge.
Potential difference equation
Work done divided by charge
V=W
Q
What is electric current the rate of flow of?
Electric charge
No current can flow when…
The circuit is broken
When does electric current flow?
When electrons move through a current, metal wire. Metals are good conductors of electricity
Passing through metallic conductors
Electricity passes through metallic conductors as a flow of negatively charged electrons.
The electrons are allowed to move from one atom to another freely? What’s this called
A sea of delocalised electrons
What is needed to let an electric current flow in it
Potential difference
How is wind produced?
As a result of giant convection currents
Wind is…
kinetic energy and is a renewable energy source
Wind turbine are used…
use the wind to drive turbines directly
What are the blades connected to?
Nacelle, which is then linked to a generator
Advantages of wind energy-
Renewable, no fuel costs
NO harmful polluting gases are produced
Disadvantages of wind energy-
Wind turbines are loud, could distract peoples lives and wildlife
Depends on the strength of wind and weather
NO wind, no electricity
Wave energy
Wave machines use the kinetic energy in the movement of waves to drive electricity generators
tidal energy
A tidal barrage is a barrier built over esturarys to make use of the kinetic energy in the water- barrage contains electrical generators
Hydroelectric power
Use kinetic energy in moving water, in a dam behind the dam holds gravitational potential energy
Advantages of hydroelectric power
No fuel costs
No polluting gases
tidal barriers and hydroelectric power stations are reliable
Disadvantages of hydroelectric power-
Destroy the habitat of estuary species
Flood farmland and push people from their homes
Rotting vegetation underwater releases methane (a greenhouse gas)
Geothermal energy
Hot water and steam can be used to drive turbines.
Solar heating
Used to generate electricity by hot water.
Evaporation
A substance in a liquid state changing into a gas due to an increase in temperature.
Amino acid
the building blocks that make up a protein molecule
Iodine test for starch
Place one spatula of the food sample on a dish or 1 cm3 if the sample is liquid.
Using a dropper, place a few drops of iodine solution onto the food.
Record any change in the colour of the solution
will then turn blue-black if there’s starch
