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
What is the function of protein?
To make new cells for growth and repeat of damaged tissues
Where can you find lipids?
- Vegetable Oils
- Nuts
- Oily fish
What is function of Lipids?
- Energy Store
- Insulation
- To make cell membranes
Where can you find Vitamin A?
- Oranges
- Green Vegetables
- Carrots
- Milk
Function of Vitamin A:
Vital for good eyesight
Where can you find vitamin B1?
- Meat
- Eggs
- Brown Rice
What is the function of Vitamin B1?
Helps release energy from Carbohydrates
Where can you find Vitamin C?
- Citrus fruit
- Green Vegetables
- Potatoes
What is the function of vitamin C?
Helps to prevent illness and make bones
Where can you find Vitamin K?
- Green Vegetables
- Tea
- Liver
What is the function of Vitamin K?
Helps the blood to clot after an injury or operation
Where can you find minerals?
- Meat
- Cereal
- Fruit and Vegetables
- Dairy products
Function of minerals:
- Iron: needed to transport oxygen in the blood
- Calcium: needed to help build bones and keep teeth healthy
- Zinc: needed to help heal wounds
Where can you find water?
- Tea
- Soup
- Cucumber
- Water melon
What is the function of water?
- Regulates body temperature
- Helps prevent constipation
- Maintains blood pressure
- Transports nutrients and oxygen to cells
- Lubricates joints and protects body organs
- Excretion
- Metabolic reactions
- Keeps the tissues in your body moist
Where can you find dietary fibre?
- Whole Grain
- Fruit
- Vegetables
- Beans
- Peas
- Lentils
- Potato (+ skin)
What is the function of dietary fibre?
Provides bulk, which helps the walls of the intestine move food and faces along the gut, preventing constipation
How do energy requirements vary with activity level, age and pregnancy?
- Children and the elderly do not require as much energy as young/middle aged adults
- Higher activity levels = higher energy requirements
- In general the greater a person’s mass, the more energy they need
- Men tend to need more energy than woman
- A woman’s energy needs increase when she is pregnant, mainly because she is carrying extra mass
What is the function of the mouth?
- Mechanical and chemical digestion
- Produces acid (provides optimum pH and kills bacteria)
What is the function of the oesophagus?
Muscular tube to move food to stomach
What is the function of the stomach?
Mechanical and chemical digestion, produces acid (provides optimum pH and kills bacteria)
What is the function of the pancreas?
Produces digestive enzymes
What is the function of the small intestine?
- Absorbing nutrients
- Duodenum is where the most chemical digestion takes place
- Illeum contains lots of white blood cells and is important in the immune response AND for absorption
What is the function of the large intestine?
- The colon absorbs water
- The rectum stores faeces
What is the function of the anus?
It is where faeces leaves the alimentary canal
What is the definition of ingestion?
The process of food entering the digestive system (through the mouth)
What is the definition of digestion (mechanical and chemical)?
- Mechanical = chewing/churning
- Chemical = enzymes breaking food down in the mouth, stomach and small intestine
What is the definition of absorption?
The movement of nutrients through the wall of the intestines into the blood
What is the definition of egestion?
Where food that is unable to be absorbed leaves the alimentary canal as faeces
What is peristalsis?
We have strong muscles lining the walls of the alimentary canal which pushes the food through in one direction (via muscle contraction)
What is assimilation?
It is the process of moving nutrients into our cells and processing/storing them
What are two key molecules in the process of assimilation?
- Glucose
- Amino acids
What is the function of the liver?
- It stores some of the glucose absorbed as glycogen
- It also converts some of the absorbed amino acids into useful proteins
How do our cells use glucose?
Cells use glucose in respiration
What are enzymes and what is their function?
- They are biological catalysts
- They speed up reactions in the body without being used up
What is the substrate of salivary amylase?
Starch
What is the action of salivary amylase
Breaks down starch to maltose
Where is salivary amylase produced?
Salivary glands
What is the substrate of protease?
Protein
What is the action of protease?
Breaks down protein to amino acids
Where is protease produced?
- Stomach
- Pancreas
What is the action of lipase?
Breaks down lipids (fats and oils) into fatty acids and glycerol
Where is lipase produced?
Pancreas
What is the substrate of pancreatic amylase?
Starch
What is the action of pancreatic amylase?
Breaks down starch to maltose
Where is pancreatic amylase produced?
Pancreas
What is the action of maltase?
Breaks down maltose to glucose
Where is maltase produced?
The small intestine
Where is bile produced?
In the Liver
Where is bile stored?
In the gall bladder
What is the role of bile?
Neutralising stomach acid and emulsifying Lipids
How is the small intestine adapted for absorption?
- Large surface area: volume Ratio
- It has a thin wall, just one cell thick
- It has many tiny villi to give it a really big surface area
