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Biology GCSE exam revision with pokemon (Not finished)
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Posted: Sun, 23/04/2023 14:43 (1 Year ago)
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1 Cell Biology
2 Organisation
3 Infection and Response
4 Bioenergetics
5 Homeostasis and response.
6 Inheritance, variation and evolution.
7 Ecology
Biology Paper 1
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-Cell Biology
-Organisation
-Infection and Response
-Bioenergetics
Biology Paper 2
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-Homeostasis and response.
-Inheritance, variation and evolution.
-Ecology
Rules:
Please DO NOT post anything in here
This is because, I cannot delete the post that people make.
It will be harder for people to read the information I put or even make them confused.
If you have any questions about what I have posted, please palpad me instead.
Posted: Sun, 23/04/2023 14:45 (1 Year ago)
Keywords:
Cells- Basic unit of living organisms.
Eukaryote- An organism made up of eukaryotic cells.
Prokaryote- An organism made up of prokaryotic cells.
Cell membrane- Separates the interior of the cell from the environment outside. It is selectively permeable.
Cytoplasm-A jelly-like fluid located outside of the nucleus.
It is where most of the cell's chemical reaction take place.
Nucleus- The control centre of the cell. It contains the genetic material, in the form of chromosomes.
Plasmids- Small rings of DNA, which can replicate and move between cells so that genetic information can be shared.
Selectively permeable- Something that can control which substances move through it.
Genetic material- Material containing information stored in DNA.
Try and remember these keyword! Rai Rai!
Posted: Sun, 23/04/2023 14:45 (1 Year ago)
There are 2 types of cell.
Eukaryotic cells:
- Found in plants, animals, fungi and protists.
- They are 10-100 micrometers in size.
- They contain a cell membrane, cytoplasm and a nucleus.
Prokaryotic cells:
- Bacteria are Prokaryotes
- They are 0.1- 5.0 micrometers in size
- They store genetic material in a single loop of DNA and may contain plasmids.
- They DO NOT have a nucleus.
- Some prokaryotic cells contain plasmids. These plasmids can replicate and move between cells so that genetic information can be shared.
- The genetic material, that is stored in a single DNA loop, is in the cytoplasm.
- They DO NOT contain mitochondria or chloroplasts.
Grimer!
Posted: Sun, 23/04/2023 20:33 (1 Year ago)
Animal Cells contain:
Cell membrane - separates the interior of the cell from environment outside. It is selectively permeable.
Nucleus - the control centre of the cell. It contains chromosomes.
Ribosomes -responsible for synthesising proteins.
Mitochondria -the organelles where aerobic respiration happens. They release energy that our cells need to function.
Cytoplasm -a jelly-like fluid that fills the cell. It is where most of the cell's chemical reactions take place.
- Most animal cells differentiate early on in their development.
- In mature animals, cells mostly divide to replace cells and repair tissues that are already present.
- New tissues are rarely created by cell differentiation.
Posted: Mon, 24/04/2023 17:42 (1 Year ago)
Permanent vacuole - a fluid-filled sac that stores water.
Chloroplasts - the site of photosynthesis.
Cell wall- maintains the shape of the cell.
Don't forget!!
These are NOT in an animal cell.
These are in a plant cell.
Posted: Mon, 24/04/2023 17:48 (1 Year ago)
Plant Cells contain:
Cell membrane - separates the interior of the cell from environment outside. It is selectively permeable.
Nucleus - the control centre of the cell. It contains chromosomes.
Ribosomes -responsible for synthesising proteins.
Mitochondria -the organelles where aerobic respiration happens. They release energy that our cells need to function.
Cytoplasm -a jelly-like fluid that fills the cell. It is where most of the cell's chemical reactions take place.
Permanent vacuole - a fluid-filled sac that stores water. It is enclosed in a membrane. It can make up as much as 90% of a plant cell's volume.
Chloroplasts - the site of photosynthesis. It contains chlorophyll which is needed for the process of photosynthesis.
Cell wall - maintains the shape of the cell. It surrounds the cell and increases the structural strength of the cell. It is made of cellulose.
- Many plant cells can differentiate throughout their lives.
- This means that plants are always able to create new tissues.
Posted: Mon, 24/04/2023 21:08 (1 Year ago)
Components of Bacterial Cells :
Cell wall - maintains the shape of the cell. It surrounds the cell and increases the structural strength of the cell. It is made of cellulose.
Cell membrane - separates the interior of the cell from environment outside. It is selectively permeable.
Plasmids - Small rings of DNA, which can replicate and move between cells so that genetic information can be shared.
Cytoplasm -a jelly-like fluid that fills the cell. It is where most of the cell's chemical reactions take place.
Flagella - a whip-like structures used for movement.
- A bacterial cell is an example of prokaryotic cell.
- The sub-cellular structures found inside some bacteria include flagella.
Posted: Mon, 24/04/2023 21:17 (1 Year ago)
Cell differentiation- a process where a cell gains new sub-cellular structures (structures inside a cell) in order to perform a specific function. When this happens the cell becomes 'specialised'.
Embryos:
- Cell differentiation happens during an organism's development.
- Organisms start as one cell.
- These cells divide to form embryos that differentiate (specialise) to produce cells that can perform all of the body's function.
Plants:
- Many plants keep their ability to differentiate throughout their life.
- Because of this, plants are always able to create new tissues.
Adult animals:
- Cell differentiation is rare in mature (adult) animals.
- Their cells mostly divide in order to replace cells and repair tissues.
- New tissues are rarely created.
Posted: Tue, 25/04/2023 06:44 (1 Year ago)
I would also like to tell you that chloroplasts and cell walls only form in plant cells. NO ANIMAL CELLS!
Pm me if ur unsure of something!(I passed this unit test 100%)
<iframe src="https://api.pokeheroes.com/widgets/pkmninteract.php?id=36323429" style="width: 100px; height: 126px; border: 0" scrolling="no"></iframe>
Posted: Tue, 25/04/2023 15:22 (1 Year ago)
Mitochondria -the organelles where aerobic respiration happens. They release energy that our cells need to function.
Powerhouse as in energy right?
I should have mentioned in the first place
Not to post anything in here
because I cannot delete the post that people made, as it will be harder for people to read the information i put or even make them confused.
If you can delete the post you made, please can you delete it.
If you have any questions about what i have posted, please palpad me instead.
Posted: Tue, 25/04/2023 18:15 (1 Year ago)
Title: continuing 1 Cell Biology
Head - contains the sperm cell's nucleus.
Acrosome - the tip of the head. It contains enzymes needed to penetrate (break into) an egg cell.
Enzyme - Biological catalysts. They speed up the rate of chemical reactions without been used up themselves.
Flagellum - used for the cell's motion.
Sperm cells
- Sperm cells are specialised to fertilise egg cells.
- They spin their tails in a corkscrew motion to move themselves towards the egg.
- The sperm fuses with the egg, sharing its genetic information to make a complete genome (all the DNA needed to make a whole organism).
3 main parts of a Sperm cell
Head
- Contains the sperm cell's nucleus, which carries one half of an organism's genetic material.
- This combines with the egg's half of genetic material to fertilise the egg.
- The top of the head is the acrosome.
Middle section
- It is filled with mitochondria to provide the sperm with the energy it needs to travel a long distance to reach the egg cell.
Flagellum
- It allows sperm cells to travel towards the egg cell.
Posted: Wed, 26/04/2023 18:11 (1 Year ago)
Axon- a part of the cell that electrical signals travel along.
Myelin sheath- stops the electrical nerve signals leaking out of the nerve cell.
Dendrites- branches of a nerve cell, that transfers electrical messages to other neurons.
Nerve Cell
- A nerve cell (neurone) is an animal cell.
- It is a eukaryotic cell.
- They are specialised to transmit electrical messages around the body.
Key features of a nerve cell:
Axon
- Part of the cell that electrical signals travel along.
- Nerve cells have a long axon. This increases the distance that electrical signals can travel.
Myelin sheath
- A sheath made of a material called myelin, surrounds the axom of the nerve cell. This stops the electrical nerve signals leaking out of the nerve cell.
- This increases the speed of transmission (travel) of electrical signals.
Dendrites
- Branches of a nerve cell.
- Several dendrites spread outwards from the cell body to transfer electrical messages to other neurons.
- Electrical messages travel between neurons at synapses.
Posted: Sun, 30/04/2023 16:31 (11 Months ago)
- Muscle cells are specialised
- They can produce force and motion.
Muscle cells have:
- Many mitochondria
- Protein fibres that contract.
- Muscle cells contain lots of mitochondria which allows them to generate lots of energy.
- Protein fibres within the cell can contract, allowing the muscle to move.
Posted: Mon, 01/05/2023 20:07 (11 Months ago)
Root hair cell
- Root hair cells are specialised.
-Their structure allows the plant to absorb more water.
- They also allow a plant to take in the minerals it needs to survive.
They have:
Long projections - increases the surface area that the plant use to absorb water and minerals.
No chloroplasts - these cells are located underground so there is no need of light for photosynthesis.
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Xylem cell
- They are specialised to transport water up the stem of a plant and into the leaves.
- They are made up of a series of connected dead xylem cells.
- The end walls of the dead cells are broken to allow water to move through.
- A substance called Lignin, strengthens the cell walls of xylem cells.
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Phloem
- They are specialised to transport food products to parts of the plant where they are needed.
- Phloem vessels are made up of columns of living cells.
- The end walls of phloem cells contain small holes to allow food products to move up and down the phloem vessels throughout the plant.
Posted: Mon, 08/05/2023 11:33 (11 Months ago)
- When using microscopes two variables matter the most:
Magnification and resolution.
Magnification - tells us how many times larger an image seen through a microscope is compared to the real object.
Resolution - the ability to distinguish between two or more objects that are close together.
Magnification= size of the image / size of the real image
Developments in Microscopy
Light microscope:
- Passes light through a specimen and creates a magnified image using lenses.
- The first microscope was made by using two lenses towards the end of the 16th century.
- This microscope had a resolution better than the human eye.
- They allowed bacteria to be seen for the first time.
- They also allowed us to see plant and animal cells as separate objects.
- It does not allow small sub-cellular structures to be seen.
Electron microscope:
- It was first used in 1933
- They work in a similar way to light microscopes. However, electrons are passed through the specimen instead of light.
- They can now resolve distances of 1nm with magnifications of x 500,000.
- They allowed scientists to see sub-cellular structures more clearly and they also allowed scientists to study how structures such as mitochondria, chloroplasts and ribosomes function.
Light Microscope Experiment
- Put a thin sample of tissue onto a microscope slide.
- Add a few drops of iodine
- Place a coverslip on top of the tissue and place the slide onto the microscope stage.
- Use the objective lens starting with the lowest magnification, and focus on the sample.
- Increase the magnification and refocus to see different features of the cell.
Posted: Mon, 08/05/2023 14:19 (11 Months ago)
Growing microorganisms
- Cultures of microorganisms can be used to investigate the effects of antibiotics and disinfectants, which both kill bacteria.
- Microorganisms can be grown in two materials that contain everything that bacteria need to survive.
Agar gel plate
- Microorganisms can be grown as colonies on an agar gel plate.
Nutrient broth
- Microorganisms can be grown within a solution of a nutrient broth.
- This contains carbohydrates as an energy source, minerals and sometimes other chemicals.
Posted: Tue, 09/05/2023 18:57 (11 Months ago)
Contamination
Risks:
-Contamination is a serious health and safety risk, as it lets other , potentially harmful bacteria grow.
Potential sources of contamination are:
-Skin
-Air
-Soil
-Water
Avoiding Contamination
Aseptic Technique
- To prevent contamination, aseptic technique are used on all apparatus.
- These techniques kill and prevents the entry of unwanted bacteria.
They involve:
-Flames
-Inoculation loops must be passed through a flame for sterilisation.
-Boiling
-Solutions and agar must be boiled for sterilisation.
-Lids
- To stop air from getting into the Petri dish, the lid must be rapidly taken off and put back on when using the inoculating loop to add bacteria to the agar.
-This lid should be taped on and the dish should be stored upside down to prevent condensation forming on the lid and then dripping onto the agar.
-Temperature
- In schools, the maximum temperature at which cultures should be incubated is 25°C.
- This extra precaution releases the risk of harmful bacteria growing.