Cells, Movement And Digestion Flashcards
Definition of Organelle:
Cell structure that is specialised to carry out a particular function or job
Definition of cell:
Basic structural and functional unit of a living organism
Definition of Tissue:
Group of cells with similar structures, working together to perform a shared function
Definition of Organ:
Structure made up of a group of tissues working together to perform specific functions
Organ System:
A group of organs with related functions, working together to perform body functions
What makes up an organ system? (In order)
Organelle - cell - tissue - organ - organ system
Structure and function of the nucleus:
The location of the cells’s DNA
Structure and function of cytoplasm:
The jelly like substance in which all the cell’s organelles are found, and in which most colour processes and reactions occur
Structure and function of the cell membrane:
The semi-permeable barrier that regulates substances entering and leaving a cell
Structure and function of the cell wall:
The rigid external coat that protects and supports plant cells
Structure and function of mitochondria:
The site of respiration
Structure and function of chloroplasts:
The site of photosynthesis in plant cells
Structure and function of ribosomes:
The site of protein synthesis
Structure and function of the vacuole:
The fluid filled cavity found in plant cells that stores water and minerals. Keep plant cells turgid
Difference Between animal and plant cells:
Plant cells have cell walls, vacuoles and chloroplasts whereas animal cells don’t
Definition of cell differentiation:
The process taking place during the development of an embryo, where cells become specialised to carry out particular functions
Why is cell differentiation important in the development of specialised cells?
- Specialised cells have a specific job
- Stem cells are unspecialised (can turn into many different specialised cells)
- Genes code for protein. All cells contain the same genes
- Genes can be on or off (on makes protein and off does not make protein)
- Different specialised cells contain the same genes, but different genes will be on, so it will make different proteins, and so create a different result (the specialised cell)
What are the pros of using stem cells in medicine?
- Can treat patients with currently untreatable conditions
- Growing organs for transplants
- Medical Research
What are the cons of using stem cells in medicine?
- No guarantee for success
- Difficult to find suitable stem cell donors
- Mutations that can behave like cancer cells
- Cells contaminated with viruses would be transferred
- Difficult to obtain and store
What are the processes whereby substances move in and out of cells?
- Osmosis
- Diffusion
- Active Transport
Definition of osmosis:
The moment of water molecules from an area of high water potential to an area of low water potential through a semi permeable membrane
Definition of Diffusion:
A passive and random process where particles move from an area of low concentration to an area of high concentration
Definition of Active Transport:
- Substances are transported passively down a concentration gradient
- Often, substances have to be moved from a low to a high concentration - against a concentration gradient
- Active Transport is a process that is required to move molecules against a concentration gradient
- The process requires energy
Describe a practical investigating the effect of concentration in the rate of diffusion:
1) Cut 11 potato chips (3cm x 1cm) using King Edward potatoes
2) Measure the mass of each chip using weighing scales
3) Place each chip in a test tube, each filled filled with different concentrations of sodium chloride (0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 and 1 mol dm -3)
4) Leave for 1 hour
5) Take the chips out of the test tubes and measure the mass of them again
6) Work out the difference between the initial and final mass of the chips and record on a table
7) Repeat 3 times and find a mean of the mass of the chips
8) Work out what the optimum concentration is for diffusion to occur (the chips with the highest recorded mass had the highest rate of diffusion = optimum concentration of sodium chloride)
Describe a practical investigating osmosis:
1) Set up 3 test tubes, each filled with water
2) Place a Visking tube in each test tube (acting as a semi permeable membrane), each filled with different substances, one with starch, one with glucose and one with starch and amylase
3) Leave for 1 hour
4) Test for the different substances in the water in each test tube
What would you see in the test tube with with the visking tube filled with starch?
- We would see a negative test for starch in water
- Starch = big molecules, - Starch = insoluble
What would you see in the test tube with with the visking tube filled with glucose?
- We would see a positive test for glucose in water
- Glucose = small molecules
What would you see in the test tube with with the visking tube filled with amylase and starch?
- We would see a positive test for glucose in water
- Amylase is an enzyme and broke down the starch, creating amylase, which has small molecules
How do you test for starch?
- Use the iodine test
- Goes from orange/brown - blue/black
How do you test for glucose?
- Use the benedict’s test
- Add benedicts solution to the substance you are testing and heat in a water bath
- Red: A lot of glucose present
- Orange: A moderate amount of glucose present
- Yellow: A small amount of glucose present
- Green: Traces of glucose present
- Blue: No glucose present
What should a balanced diet be made up of?
Appropriate portions of carbohydrates, protein, lipids, vitamins, minerals, water and dietary fibre
Where can you find carbohydrates?
- Bread
- Pasta
- Rice
- Potatoes
What is the function of carbohydrate?
Slow release of energy
Where can you find protein?
- Red meat
- Fish
- Eggs
- Beans
- Lentils
- Nuts