Assesment B1 Revision Flashcards
The difference between prokaryotic and eukaryotic cells
Eukaryote cells are complex and include animal and plant cells, prokaryotic cells are smaller and simpler e.g bacteria
Define each cell function
Nucleus- contains DNA, controls the activity
Cytoplasm- chemical reactions take place, contains enzymes
Cell membrane- controls movement and holds it together
Mitochondria- used for respiration, transfers energy
Ribosomes- where proteins are made
What is the equation for magnification?
Top: image size
Left: magnification
Right: real size
Why are there specialised cells?
For reproduction, rapid signaling, contraction, absorbing water and minerals and transporting substances
What is mitosis?
When the chromosomes line up in the center or the cell, cell fibres pull them apart, the two arms of each chromosome go to the opposite ends of each cell. Cell membranes form around each set of chromosomes, these become the nuclei of the cell then the cytoplasm and cell membrane divide making two new daughter cells
What is differentiation?
When a cell changes to become a specialised cell to carry out a new process
Stem cells are found in the…
Meristem/ bone marrow (where growth happens)
What is osmosis?
The movement of water across a partially permeable membrane by by diffusion
What happens to the water in an osmosis experiment?
If the cylinders draw in water they will have increased in mass, if it’s drawn out then it’s decreased in mass
What is active transport?
It allows the plant to absorb minerals from a very dilute solution against the concentration gradient. This process requires energy from respiration to work. E.g taking in glucose from the gut
What are enzymes?
- They act as biological catalysts,
- they reduce the need for high temperature
- they speed up useful chemical reactions in the body.
- Every enzyme has an active. made up of chains of amino acids which are folded into unique shapes to carry out their job
- if the substrate does fit it’s active site it won’t be a catalyst reaction
What is a catalyst?
A substance which increases the speed of a reaction without being changed or used up in the reaction
State what happens in a catalyst reaction
- The substrate binds to the active site to fer an ‘induced fit’
- they have an optimum temperature for the enzyme-catalyst reaction which is normally 0-45°
- If it’s too hot the bonds in the enzyme break, its denatured
- they also have an optimum pH normally 7 unlike pepsin which breaks down stomach acid and works best at pH2
What are each tests?
Benedict’s: sugars blue to green. Yellow to brick red
Iodine: starch blue black
Biuret: proteins blue to pink or purple
Sudan III: lipids bright red
What is the amylase?
It is an example of a carbohydrase, it breaks down starch and it’s found in the salivary glands, the pancreas and the small intestine
What are proteases?
They convert proteins into amino acids which are found in the stomach (called pepsin there), the pancreas and small intestine
What are lipases?
They convert lipids (fats and oils) into glycerol and fatty acids and are made in the pancreas and the small intestine
What is bile?
It’s produced in the liver and stored in the gall bladder before being released into the small intestine. The hydrochloric acid in the stomach is too acidic in the stomach for the enzymes in the small intestine to work properly. So bile is alkaline which neutralisés the acid. It emulsifies fats (breaks down) this gives the enzyme a large surface area for it to work on making digestion faster
State each function of the catalyst reactions
Salivary glands: produce amylase enzymes in the saliva
Liver: where bile is produced
Gall bladder: where bile is stored
Large intestine: where excess water is absorbed from food
Small intestine: produces protease, amylase and lipase for digestion
Pancreas- produces protease, amylase and lipase
Stomach- produces protease and pepsin and hydrochloric acid to kill bacteria and give the pH2 for protease to work
What is gas exchange?
The lungs contain alveoli, surrounded by a network of blood capillaries where gas exchange happens. The blood passing next to the alveoli contains a lot of carbon dioxide from the lungs. Oxygen diffusés out the alveolus into the blood then the carbon dioxide diffuses into the blood
What happens in the lungs?
The air goes through the trachea then splits into two tubes called bronchi going to each lung. Which then splits into even smaller tubes called bronchioles. It ends at a small bag called alveoli where gas exchange happens.
What’s the types of blood vessels?
Arteries: carry the blood AWAY from the heart
Veins: carry the blood to the heart
Capillaires: involved in the exchange of materials at the tissues
Arteries branch into capillaries
What is plasma?
It’s the liquid that carries everything in blood
- Carbon dioxide: from the organs to the lungs
- Urea: from the liver to the kidneys
- Hormones
- Proteins
- Antibodies and antitoxins
What are the pros and cons of statins reducing high cholesterol?
It reduces the risk of stokes, coronary heart disease and heart attacks. It increases HDL cholesterol, statins also help prevent other diseases.
-Statins must be taken regularly so there’s the risk someone might forget
Negative side effects like headaches, kidney failure, liver damage and memory loss. Statins aren’t instant effect
