BIOLOGY PAPER 1 - extra notes/topics Flashcards
(22 cards)
List the differences between arteries and veins
- veins have valves, arteries don’t
- arteries have a narrower lumen than veins to carry blood at a higher pressure
- arteries have a thicker layer of muscle tissue
- arteries have a thicker layer of elastic tissue
how do you check if results are repeatable
You repeat the investigation and see if any of the results are similar
what are pacemakers used for
Pacemakers are used to treat an irregular heartbeat and is placed in the right atrium
what happens if a plant has magnesium deficiency
- yellow leaves, caused by a lack of chlorophyll, so less light is absorbed for photosynthesis and the rate of photosynthesis deceases. Less glucose is produced and less is converted into protein for growth or less energy is released for growth, leading to stunted growth
Controls of the rate of photosynthesis investigation
( if you are changing power of light)
- concentration of carbon dioxide
- temperature of water
- distance of bulb from pondweed
- repeat investigation and calculate mean to eliminate any anomalies
What is water loss in leaves controlled by
Controlled by guard cells that open and close the stomata
how is water transported from the roots to the rest of the plant
- water is transported in the xylem up the plant, and evaporates from the leaves through the stomata
a plant will lose more water if… what?
- it has bigger leaves
- more leaves
- more stomata on the leaves
what is a double circulatory system
Blood gets pumped into the lungs by the right side of the heart
Blood gets pumped to the body by the left side of the heart
Definition of an enzyme
a protein that functions as a biological catalyst without being used up
differences between a eukaryotic cell and a prokaryotic cell
- prokaryotic cells are smaller
- prokaryotic cells have no mitochondria
- prokaryotic cells have no nucleus
- prokaryotic cells have a single loop of DNA
- prokaryotic cells have plasmids
what happens in the different stages of the cell cycle
stage 1: DNA replicates and subcellular structures increase in number
Stage 2: one set of chromosomes is pulled to each end of the cell
Stage 3: cytoplasm and cell membrane divide to form 2 new cells
what is the lock and key theory
- enzyme binds to substrate because they are complementary
- so substrate is broken down into products
- products are released and the enzyme isn’t used up
presence of glucose and starch in a plants
Glucose is produced for photosynthesis and used for respiration
Excess glucose is stored as starch
Why a plant in the dark contains glucose but doesn’t contain starch
Because there is no light, the plant can’t photosynthesise and produce glucose for respiration. So starch stores are converted back into glucose, so it can be used for respiration.
why could a plant have yellow leaves
1) Lack of magnesium: Not enough chlorophyll to absorb light for photosynthesis, not enough glucose to release energy for growth
2) Infection by pathogen/bacteria: Leaves become yellow so less photosynthesis and not enough glucose to release energy for growth
3) Infection by aphids which removes sugars from phloem, not enough glucose to release energy for growth
4) Lack of light: chlorophyll breaks down, not enough glucose to release energy for growth
what is homeostasis
maintenance of a constant internal environment.
what are nitrate ions needed for in plants
they are needed for amino acids / proteins
what do bacteria in the nitrogen cycle do
- nitrogen fixing bacteria converts nitrogen gas into nitrates
- they live freely in soil or root nodules
what are antibiotics
Antibiotics are substances that slow down or stop the growth of
bacteria
. They are commonly prescribed medicines, examples include
penicillin
and amoxicillin.
Why do antibiotics not work on viruses
viruses live inside the host cells, and antibiotics can’t reach them without harming the body’s own cells
