Year 9 Jan Exam Flashcards
What is active transport?
Movement of dissolved molecules in or out of a cell through the cell membrane. From lower to higher concentration
What is osmosis?
Diffusion of water molecules from a dilute solution to a more concentrated solution across selectively permeable membrane
Why does a larger surface area increase the rate of diffusion?
Because there is more space for molecules to diffuse across the membrane
Define diffusion.
The random movement of a substance from a region of high consent ration to a region of low concentration
How do you convert cm to mm?
x10
How do you convert cm to m?
Divide by 1000
How would you convert 30cm to nanometers?
First you divide x10 to get 300mm then x1000 to get 300,000um then x1000 again to get 300,000,000nm
How would you convert 480,000,000nm into cm?
Divide 480,000,000 by 1000 to get 480,000 then divide by 1000 again to get 480 then divide by 10 to get 48
What is a bacteria cell?
Also called prokaryotic. Meaning they DON’T have a nucleus or any other structure which are NOT surrounded by membranes
What is an animal cell?
Also called eukaryotic. Meaning they DO have a nucleus and other structures which ARE surrounded by membranes. Similar to a plant cell
What is a plant cell?
Also called eukaryotic. Meaning they DO have a nucleus and other structures which ARE surrounded by membranes. Similar to a animal cell
How do you work out the actual size, image size and magnification of an object under a microscope or pic of an object under the microscope?
- Measure the scale bar in mm
- Convert to um (x1000)
- Magnification = scale bar image divided by actual scale bar length (written on the scale bar)
What is the equation for working out the magnification size?
I
A x M
What are the properties of light and electronic microscopes?
An electronic microscope has a much higher resolution than a light microscope
What are the uses of light and electronic microscopes?
Light microscopes are used to study living cells and for regular use when relatively low magnification and resolution is enough
What are the advantages of light and electronic microscopes?
They have a much higher range of magnification (detect smaller structures). They have a much higher resolution (provide clearer and more detailed images)
What are the disadvantages of light and electronic microscopes?
Light microscopes can only be used in the presence of light and are very expensive
Why is a sperm cell specialised to its function?
- It has a tail which helps it swim to the egg
- It contains the nucleus in the head that fertilises the egg
- It contains mitochondria to provide the energy it needs to reach the egg
Why is a neurons specialised to its function?
- They carry electrical impulse from one place to another
- They have a long fibre to carry messages up and down the body over long distances
Why is a muscle cell specialised to its function?
They are specially adapted to allow for movement. Many muscle cells grouped together make muscle tissue
Why is a root hair cell specialised to its function?
- Taking up water and mineral ions by having a large surface area to increase the rate of absorption
- Contain lots of mitochondria which releases energy from glucose during respiration in order to produce the energy for active transport
Why is a xylem cell specialised to its function?
- They loose their end walls so the xylem forms a continuous hollow tube
- Strengthens by lignin which gives strength and support to the plant
Why is a phloem cell specialised to its function?
Thy have perforated ends so that one cell is connected to the next allowing the free flow of the cytoplasm
Does the same type of specialise cell work with others to form tissues?
Yes
Can different tissues work together to form organs?
Yes
Can different organs work together to for organ systems?
Yes.
1. Reproductive system
2. Urinary system
3. Cardiovascular system
4. Endocrine system
5. Nervous system
6. Digestive system
7. Respiratory system
8. Lymphatic system
9. Muscular system
10. Skeletal system
11. Integumentary system
Describe the function of cell structures and organelles.
Contains genetic materials including DNA which controls the cells activities
Define a prokaryote cell.
A prokaryote cell is a single celled organism that lacks a nucleus and other membrane-bound organelles.
Define a eukaryotic cell.
Organisms who’s cells contain a nucleus and other membrane-bound organelles
What is a plant cell made up of?
Cell wall, cell membrane, cytoplasm, vacuole, nucleus and chloroplast
What is an animal cell made up of?
Nucleus, cell membrane, cytoplasm and mitochondria
Why is a bacteria cell made up of?
Ribosomes, a chromosome and plasmids
