[qdeck card_back=”none” ]
[h] iGCSE Biology Notes Organization of the organism
[q] Label a cell
[a]
[q] What is inside a cell?
What does the cytoplasm do?
[a]
- Was we’ve said, the cytoplasm is like the water in a water balloon.
- All the other organelles of a cell float in the cytoplasm
- Most importantly though, The cytoplasm is where most chemical reactions happen inside a cell.
- These are all the reactions that keep cells working and keep living things alive!
[q] What is inside a cell?
What does the cell membrane do?
[a]
- The cell membrane is the edge of a cell
- It contains the cytoplasm and all the other organelles
- It’s main job however is this: The cell membrane controls what enters and what leaves a cell.
- This is really important to ensure a cell can get whatever it needs, can remove any waste, to ensure nothing important gets out and to prevent some things from entering.
[q] What is inside a cell?
What do the mitochondria do?
[a]
- The mitochondria are very important for a cell
- Mitochondrion is the singular, mitochondria is the plural. Most cells have many mitochondria.
- This is what a mitochondrion does: The mitochondria release energy for the cell.
- Energy is essential to do anything, including most chemical reactions that happen in the cell.
[q] What is inside a cell?
What does the nucleus do?
[a]
- The nucleus might be the most important part of a cell
- The nucleus controls the activities of the cell and stores the DNA.
- DNA is like a code, a set of instructions for the cell to follow. Believe it or not, but all the instructions to make a whole organism, like you, can be found in each and every one of your cells.
[q] What is inside a cell?
What do the ribosomes do?
[a]
- Ribosomes are smallest organelles. Often you can’t even see them!
- They have a very important role though; Ribosomes synthesise protein for a cell.
- Proteins are incredibly important for every living thing. Many important compounds that living things need are proteins. The DNA in the nucleus has the instructions for ribosomes to make proteins.
[q] What is special about a plant cell?
What things will you find in a plant cell?
[a]
- On the right is a diagram of a typical plant cell.
- An plant cell is the kind of cell that makes up plants, everything from algae to roses, seaweed to pine trees, mosses to ferns.
- Everything found in animal cells are also found in plant cells, can you label them?
- However, plant cells have some extra features.
- They have a cell wall, which on the outside of the cell membrane
- They have a large vacuole, a large storage space
- They have chloroplasts, green organelles a bit bigger than mitochondria
[q] What is inside a plant cell?
What does the cell wall do?
[a]
- A cell wall is found on the outside of the cell membrane.
- The cell wall is made of a substance called cellulose which makes it strong
- This is the role of the cell wall; The cell wall protects the plant cell and keeps the structure of the cell.
- The cell wall is the reason why most plant cells are cube or cuboid in shape (remember cells and 3-D, so they are not square or rectangular!)
[q] What is inside a plant cell?
What does the vacuole do?
[a]
- Plant cells have a large vacuole, which is a large storage organelle, often larger than the nucleus
- Animal cells also have vacuoles, but they have many smaller ones, never a large singular one.
- This is the role of the vacuole; The vacuole stores cell sap and keeps a plant cell turgid.
- Turgid means the pressure in the plant cell is high so the cell is sturdy, like a fully inflated car tire. Cell sap is a sugary solution which acts as a store of energy
[q] What is inside a plant cell?
What do the chloroplasts do?
[a]
- Chloroplasts are green organelles found in most plant cells. They are green because the contain a green pigment called chlorophyll.
- They are slightly larger than mitochondria and have a complex internal structure.
- The role of the chloroplast is very important; Chloroplasts perform photosynthesis which produces glucose for the plant.
- Glucose is the main source of energy for all living things. It is the job of the mitochondria to release the energy from glucose.
- Plants can’t eat food like animals can, so the only way plants can get glucose is to do photosynthesis, which uses light energy to produce glucose.
[q] What is a specialised cell?
What does specialised mean?
[a]
- So, a specialised cell is a cell that is adapted for its specific function.
- Let’s take a palisade cell for an example.
- Its function is to perform photosynthesis to produce glucose. They are found in the leaves of plants
- We know that the organelle that performs photosynthesis is the chloroplast.
- A palisade cell is adapted for its function because it has lots of chloroplasts so it can perform more photosynthesis.
[q] Match the function to the adaptation
Here are 8 functions and 8 adaptations, do you think you can link them?
[a] Hint: You don’t have to do them in order, start with the easier ones and work from there!
[q] Match the function to the adaptation
Here are 8 functions and 8 adaptations, do you think you can link them?
[a] Hint: You don’t have to do them in order, start with the easier ones and work from there!
[q] Specialised cells
Can you recognize any of these cells?
What do they do?
How are they adapted?
[a]
[q] Magnification
How can we work out the magnification of an image?
[a]
- This is the equation to find magnification, and you can rearrange it to get the size of the image or the actual size of the object.
- Sometimes you will have to measure the size of the image yourself with a ruler, remember to always use millimetres!
[x] Exit text
(enter text or “Add Media”; select text to format)
[/qdeck]