Biology paper 1 Flashcards
Cells -
Contains genetic information that controls the functions of the cell.
Nucleus
Cells -
Controls what enters and leaves the nucleus.
Cell membrane
Cells -
Where many cell activities and chemical reactions in the cell occur.
Cytoplasm
Cells -
Provides energy from aerobic respiration
Mitochondria
Cells -
Synthesis (makes) proteins
Ribosome
Cells -
Where photosynthesis occurs
Chloroplast
Cells -
Used to store water and other chemicals as cell sap
Permanent vacuole
Cells -
Strengthens and supports the cell. (Made of cellulose in plants).
Cell wall
Cells -
A loop of DNA, not enclosed within a nucleus.
DNA loop
Cells -
A small circle of DNA, may contain genes associated with antibiotic resistance.
Plasmid
Cells -
Acrosome contains enzymes to break into egg; tail to swim; many mitochondria to provide energy to swim.
Sperm cell
Cells -
Long to transmit electrical impulses over a distance.
Nerve cell
Cells -
Contain protein fibres that can contract when energy is available, making the cells shorter.
Muscle cell
Cells -
Waterproofed cell wall; cells are hollow to allow water to move through.
Xylem cell
Cells -
Some cells have lots of mitochondria for active transport; some cells have very little cytoplasm for sugars to move through easily.
Phloem cell
Cells -
Long extension to increase surface area for water and mineral uptake; thin cell wall.
Root hair cell
Cells -
Contains: cytoplasm, nucleus, ribosome, mitochondria and cell membrane.
Animal cell
Cells -
Contains: cytoplasm, nucleus, ribosome, mitochondria, cell membrane, chloroplast, vacuole and cell wall.
Plant cell
Microscopy -
The degree by which an object is enlarged
Magnification
Microscopy -
The ability of a microscope to distinguish detail.
Resolution
Microscopy -
Basic microscope with a maximum magnification of 1500x. Low resolution.
Light microscope
Microscopy -
Microscope with a much higher magnification and resolving power than a light microscope. This means that it can be used to study cells in much finer detail.
Electron microscope
Mitosis and the cell cycle
- Number of sub-cellular structures increase
- Number of chromosomes double
- One set of chromosomes is pulled to each end of the cell
- The nucleus divides
- Cytoplasm and cell membranes divide to form two identical cells
Stem cells -
Can divide into most types of cells
Used for therapeutic cloning
Embryonic stem cells
Stem cells -
Can divide into a limited number of cells
Adult stem cell
Stem cells -
Found in plants
Can differentiate (divide) into any type of plant cell
Meristem
Pros of using stem cells
Treatment of diseases such as diabetes, dementia and paralysis
Cons of using stem cells
Ethical and religious objections
Can transfer viruses held within cells
Transport across membranes -
Diffusion definition
Spreading out of the particles resulting in a net movement from an area of higher concentration to an area of lower concentration
Transport across membranes -
Diffusion use
Oxygen and carbon dioxide in gas exchange (leaves and alveoli)
Urea from cells into the blood plasma for excretion in the kidney
Transport across membranes -
Osmosis definition
The diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.
Transport across membranes -
Osmosis use
Movement of water into and out of cells
Transport across membranes -
Active transport definition
The movement of substances from a more dilute solution to a more concentrated solution. Requires energy from respiration.
Transport across membranes -
Active transport use
Absorption of mineral ions (low concentration) from soil into plant roots. Absorption of sugar molecules from lower concentration in the gut into the blood which has a higher sugar concentration.
Factors affecting diffusion -
Difference in concentrations explanation
The greater the difference in concentrations, the faster the rate of diffusion.
Factors affecting diffusion -
Temperature explanation
Particles move more quickly at higher temperatures, so rate of diffusion increases.
Factors affecting diffusion -
Surface area of membrane explanation
The greater the surface area the quicker the rate of diffusion.
Adaptation of exchange surfaces
- Large surface area
- Thin membrane (provides short diffusion path)
- Ventilation (in animals for gas exchange - maintains a concentration gradient)
- Efficient blood supply (in animals - maintains a concentration gradient
Organisation -
Tissue
A group of cells with a similar structure and function
muscle, tissue
Organisation -
Organ
A group of tissues performing a specific function
heart, leaf
Organisation -
Organ system
A group of organs that perform a specific function (digestive system)
Enzymes key terms -
Enzyme
A biological catalyst that can speed up the rate of reaction without being used itself. Made of a large protein molecule.
Enzymes key terms -
Substrate
The chemical that fits into the active site of an enzyme
Enzymes key terms -
Lock and key model
Only one type of substance can fit into the active site of an enzyme, like a key fits into a lock.
Enzymes key terms -
Denatured
When the active site of an enzyme changes shape and the substrate can no longer fit in. Can be caused by pH or temperature.
Testing for biological molecules -
Starch chemical test
Add orange/brown iodine solution
Testing for biological molecules -
Starch positive result
Colour turns blue/black
Testing for biological molecules -
Sugar chemical test
Add blue Benedict’s solution. Place in a boiling water bath for 5 minutes
Testing for biological molecules -
Sugar positive result
Colour turns green / yellow / orange / brick red
Testing for biological molecules -
Protein chemical test
Add blue Biuret solution
Testing for biological molecules -
Protein positive result
Colour turns lilac/purple
Testing for biological molecules -
Lipid chemical test
Add ethanol and decant into water
Testing for biological molecules -
Lipid positive result
Cloudy white emulsion
Human digestive enzymes -
Amylase
Function - breaks starch into sugars
Sites of production - salivary glands, pancreas, small intestine
Sites of action - mouth, small intestine
Human digestive enzymes -
Protease
Function - breaks proteins into amino acids
Sites of production - stomach, pancreas, small intestine
Sites of action - stomach, small intestine
Human digestive enzymes -
Lipase
Function - breaks lipids (fats) into fatty acids and glycerol
Sites of production - pancreas, small intestine
Sites of action - small intestine
Other chemicals -
Hydrochloric acid
Acid with pH produced by the stomach. Unravels proteins.
Other chemicals -
Bile
Emmulsifies fats (turns them into droplets to give a greater surface area). It is alkaline so neutralises acids from the stomach. Produces in liver, stored in gall bladder and is released into the small intestine.