Cell structure and transport (The microscope (Calculating magnification (…
Cell structure and transport
-Magnification= image size/ size of real object
-Image size= magnification x size of real object
-Size of real object= image size/ magnification
(Remember money is silly)
1 kilometre (km)=1000 metres
1m= 100 cm
1 micrometre= 1000 nanometres
Light microscopes magnify up to about x2000, and have a resolving power of about 200 nanometres
Electron microscopes magnify up to about x2 000 000 and have a resolving power of around 0.2 nanometres
See quizlet deck for a test >
Resolution is the ability to distinguish between two separate points and it is the resolving power of a microscope that affects how much detail it can show
Animal and plant cells
Animals cellls- structure and function
The nucleus- Controls all the activities of the cell and is surrounded by the nuclear membrane. It contains the genes on the chromosomes that carry the instructions for making the proteins needed to build new cells or new organisms
The cytoplasm- a liquid gel in which the organelles are suspended and where most of the chemical reactions needed for life take place
The cell membrane- controls the passage of substances such as glucose and mineral ions into the cell. It also controls the movement of substances such as urea or hormones out of the cell.
The mitochondria- Structures in the cytoplasm where aerobic respiration takes place, releasing energy for the cell.
The ribosomes- Where protein synthesis takes place, making all the proteins needed in the cell.
Plants cells- structure and function
Make their own food by photosynthesis
All plant cells have a cell wall made of cellulose that strengthens the cell and gives it support
Chloroplasts- Found in all the green parts of a plant. Contain a substance called chlorophyll (absorbs light so the plant can make food for photosynthesis.
Vacuole- Space in the cytoplasm filled with cell sap. Important for keeping the cells rigid to support the plant
Plant cells have all the features an animal cell does with some extras described below
Eukaryotic and prokaryotic cells
Examples are animal and plant cells // All animals (inc. humans), plants, fungi and protista
DNA forms structures called chromosomes contained within the nucleus
Consist of... a cell membrane, cytoplasm and genetic material enclose in the nucleus (called DNA)
Example is bacteria (single celled living organisms)
Significantly smaller than eukaryotic
Can't see bacteria without an extremely powerful microscope, culturing bacteria on and agar plate allows you to see a bacterial colony with the naked eye
Bacteria have cytoplasm and a cell membrane surrounded by a cell wall (doesn't contain cellulose like a plant cell) Some types have a flagellum (a long protein strand that lashes about and helps the movement of the cell
In prokaryotic cells the genetic material is not enclosed in the nucleus and the bacteria chromosome is a single DNA loop found free in the cytoplasm
Contain small rings of DNA called plasmids
Some bacteria are harmful- can cause diseases in humans and other animals and plants
They can decompose and destroy stores food
1.Prokaryotic are much smaller in size
2.The genetic material is not enclosed in the nucleus
The genetic material is a single DNA loop and there may be one or more small rings of DNA called plasmids
They don't contain mitochondria or chloroplasts
Specialization in animal cells
Specialized cells are developed to carry out particular jobs.
As an organism develops, cells differentiate to form different types of specialized cells. Animals cells differentiate earlier then plant cells that do it through life.
Specialized to carry electrical impulses around the body of an animal. Provide rapid communication system between the different parts of the body
Lots of dendrites to make connections to other nerve cells
An axon that carries the nerve impulse from one place to another. They can be very long
3.The nerve endings pass the impulses to another cell or between a nerve cell and a muscle in the body using special transmitter chemicals. Contain lots of mitochondria to provide energy needed to make the transmitter chemicals.
Specialized so they can contract and relax. Work together in tissues called muscles. They contract and relax in pairs to move the bones of the skeleton, eg so vertebrates can move on land and in water
Contain special proteins that slide over each other making the fibres contract
Contain many mitochondria to transfer the energy needed for the chemical reactions that take place as the cells contract and relax
Can store glycogen, a chemical that can be broken down and used in cellular respiration by the mitochondria to transfer the energy needed for the fibres to contract
Usually released a long way from the egg they are going to fertilize. Contain genetic info from the male parent. Sperm cells need to move through water or the female reproductive system to reach an egg. Then they have to break the egg
A long tail whips from side to side to help move the sperm through water or the female reproductive system
The middle section is full of mitochondria, which transfer the energy needed for the tail to work
The acrosome stores digestive enzymes for breaking down the outer layers of the egg
A large nucleus contains the genetic information to be passed on
Specialization in plant cells
Root hair cells
Found close to the tips of growing roots. Plants need to take in lots of water (ans dissolved mineral ions). Root hair cells help to take them in more efficiently. Always relatively close to the xylem tissue (which carries water and ions to rest of the plant) Mineral ions are moved into the root hair cell by active transport.
They greatly increase the surface area available for water to move into the cell
They have a large permanent vacuole that speeds up the movement of water by osmosis from the soil across the root hair cell
They have a lot of mitochondria that transfer the energy needed for the active transport of mineral ions into the root hair cells.
Plants make their own food by photosynthesis. Some plants can photosynthesise