Key Concepts in Biology Flashcards
What components make up the animal cell?
Nucleus, Cytoplasm, Ribosomes, Mitochondria and Cell membrane.
What components make up the plant cell?
Nucleus, Cytoplasm, Ribosomes, Mitochondria, Cell membrane, cell wall, vacuole and chloroplast.
What is the function of the Nucleus?
It is where all the genetic information is stored.
What is the function of the Cytoplasm?
A gel-like substance that controls chemical reactions.
What is the function of the Cell membrane?
It holds the cell together and it also controls what enters and leaves the cell.
What is the function of the Mitochondria?
It is where respiration takes place.
What is the function of the Ribosomes?
Where protein synthesis takes place.
What is the function of the cell wall?
It helps strengthen and support the cell. It is also made of cellulose.
What is the function of the Vacuole?
It contains cell sap and it maintains the internal pressure to support the cell.
What is the function of the chloroplast?
It is where photosynthesis takes place. It contains a substance called chlorophyll which the pigmentation to the plant.
State the different components of Bacteria.
Ribosomes, Cell membrane, plasmid DNA, Cytoplasm, Flagellum and chromosomal DNA.
What is the function of the Chromosomal DNA?
It is one long single chromosome that controls activities of the cell and it floats in the cytoplasm.
What is the function of the Plasmid DNA?
They are small hoops of DNA that contains genes for drug resistance and can be passed between bacteria.
What is the function of the Flagellum?
It is a long hair-like structure that rotates to help move the bacteria. This helps the bacteria move away from harmful substances.
State the different components of the sperm cell.
Middle piece (contains mitochondria) , haploid nucleus, tail and acrosome.
Explain the adaptations of the sperm cell.
It has a tail to help swim to the egg. it has lots of mitochondria in the middle piece to provide energy to swim the distance. It has acrosomes in front of the “head” where enzymes are stored to digest through the membrane of the egg cell. It has haploid nucleus.
State the different components of the egg cell.
Mitochondria, haploid nucleus, cell membrane and cytoplasm.
Explain the adaptations of the egg cell.
It has many nutrients in the cytoplasm to feed the embryo. It has a haploid nucleus. Right after fertilisation the membrane changes structure to prevent another sperm cell entering.
What is the function of ciliated epithelial cells?
Moving materials. They line the surfaces of organs
Explain the function of ciliated epithelial cells?
Hair-like structure on the top surface of the cell. The cilia beat to move substances in one direction, along the surface of the tissue.
What are catalysts?
A substance which increases the speed of reaction which being changed or being used up in the reaction.
What is a biological catalyst?
Enzyme
Explain the structure of an enzyme
- All enzymes have an active site specific to the substrate shape
- Where the substrate and the enzyme meet it catalyses a reaction
- the substrate fits into the enzyme like a lock and key
What does it mean when a enzyme denatures?
When the pH or temperature is too high or low the bonds holding the enzyme break down causing the enzyme’s active site to change shape so the substrate doesn’t fit anymore.
What does it mean when something reaches the optimum point?
The enzyme is working at its best.
Explain the practical of pH on Enzyme Activity
- Put drop of iodine solution into every spotting tile
- Heat water until 35 degrees
- Add 3cm^3 of amylase solution and 1cm^3 of buffer solution with pH of 5 to a boiling tube with syringe
- Put boiling tube in beaker and wait five minutes
- With syringe add 3cm^3 of starch solution to boiling tube
- Mix contents and start clock
- Use pipette to take a fresh sample from the water every 10 seconds and add to spotting tile
- If browny-orange the starch is no longer present#
What is the function of enzymes?
Break down big molecules. And joining molecules.
What does the enzyme carbohydrase break down?
Carbohydrates into simple sugars
or
Starch into maltose
What does the enzyme protease break down?
Proteins into Amino acids
What does the enzyme lipase break down?
Lipids into glycerol and fatty acids
What is the test for sugar molecules?
Benedict’s Reagent
What is the test for starch molecules?
Iodine solution
What is the test for lipid molecules?
Emulsion Test
What is the test for protein molecules?
Biuret Test
Explain the Benedict’s Reagent test
- Add sample to reagent
- Heat reagent in bath of 75 degrees
- If positive the colour will change. The higher the concentration the further the colour change
- It goes from Blue > Green > Yellow > Orange > Brick Orange
Explain the Iodine test
- Add iodine solution to sample
- If positive it will change from browny-orange to blue-black if starch if present
- If negative it will stay browny-orange
Explain the Emulsion test
- Shake test substance with ethanol until dissolved
- Pour solution into water
- If positive the lipids will precipitate out the liquid and show as a milky emulsion
Explain the Biuret Test
- Adds drops of potassium hydroxide to make solution alkaline
- Add bright blue copper(II) sulfate
- If there is no protein it will stay blue
- If there is protein it will turn purple
Define diffusion
The movement of particles from a higher concentration to a lower concentration.
Define osmosis
The movement of water particles across a semi-permeable membrane to a region of higher water concentration to a region of lower water concentration.
Define active transport
The movement of particles across a membrane from a lower to a higher concentration using energy transferred during respiration.
Explain the osmosis experiment
- Prepare sucrose solution of different concentrations of pure water and very concentrated sucrose solution
- Cut potatoes making sure they are the same mass
- Place one in each solution
- Leave in solution for at least 40 minutes
- Remove potatoes and dry with paper towel
- Measure the final mass
How do light microscopes work?
By passing light through the specimen
How do electron microscopes work?
Using electrons to see the specimen instead of light
What are the advantages of light microscopes?
- Can view live specimen]
- Not very expensive
- The original colour of the specimen can be seen
What are the disadvantage of light microscopes?
- The resolution and magnification is relatively low
What are the advantages of electron microscopes?
- Higher resolution and magnification
What are the disadvantages of electron microscopes?
- Cannot view live specimen
- Expensive
How do you use a light microscope?
- Take thin slice and put specimen on slice
- Add a stain if specimen
- Cover the slice with a cover slip
- Place underneath the clips on the microscope and clip the slide on the stage
- Start at the lowest powered objective lens
- Then using objective lens move the stage up until focussed
- Then look into the eyepiece
- If higher magnification is needed change the power of the lens
Total magnification formula
eyepiece lens magnification x objective lens magnification
Magnification formula
image size / real size
Image size formula
magnification x real image
Real image size formula
image size / magnification
Conversion chart
https://library.cgpbooks.co.uk/digitalaccess/BER45DF/Online/
page 15
Where is amylase made?
- Salivary glans
- Small intestines
- Pancrease
What is the function of amylase?
It catalyses the break down of starch into glucose
What is the function of protease?
Digests proteins into amino acids
Where is protease found?
- stomach
- small intestines
- pancreas
What is the function of Lipase?
It catalyses the breakdown of lips into fatty acids and glycerol
