Question | Answer |
Organelles in order that are responsible for production of proteins (Eukaryote) | Ribosome on RER (Rough Endoplasmic Reticulum), vesicles to Golgi Apparatus, vesicles to plasma membrane for secretion |
Function of mitochondrion (mitochondria) | Site of aerobic respiration. They are found in large numbers in cells that are active and require a lot of energy. |
Lysosome | Vesicle that contains digestive enzymes. Kept separate from cell contents by the surrounding membrane. Digest invading cells and worn out cell parts. |
Organelle that is the site of photosynthesis | Chloroplast-surrounded by a double membrane. Has membranes inside called thylakoid membranes arranged in stacks called grana. |
Differences between Prokaryotic and Eukaryotic cells | Prokaryotic cells are smaller, DNA is circular and free in the cytoplasm (non nucleus). Eukaryotes have membrane bound organelles such as mitochondria, Prokaryotes do not. Flagella in Eukaryotes are made of microtubules in a 9+ 2 formation. |
Magnification formula | Image Size Divided by Object Size |
How many micrometres in 1 millimetre | 1000 |
Object size formula | Image size divided by Magnification |
Use of light microscopes | Looking at whole cells or tissues. Magnification limit about 1500, lower resolution than electron microscopes. |
Laser scanning confocal microscopes are | a special type of light microscope that uses laser beams to scan something that has been tagged with a fluorescent dyes.Much clearer than normal light microscope, can look at different depths in thick specimens. |
2 types of electron microscope | Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM). |
TEM uses | Produce 2D images with very high resolution so can be used to look at small organelles such as ribosomes. They can look at internal parts of an organelle. They need to be thinly sliced. Can magnify one million times. |
SEM uses | Images show the surface of the specimen. They can be 3D but give lower resolution than TEM. Can magnify half a million times. |
Resolution is | How detailed an image is. How well the microscope distinguishes between two points that are close together. |
Some properties of water that are important to life | High specific heat capacity-means takes a lot of energy to heat it up, so stable habitat. High latent heat of evaporation- good for cooling by sweating. Cohesive (attraction between molecules) good for transpiration in plants. Good solvent-part of blood |
Condensation reaction | used to join monomers to make a polymer. It forms a chemical bond between 2 monomers and releases a molecule of water. |
Carbohydrate monomers are called | Monosaccharides |
2 forms of glucose and the difference between them. | Alpha and Beta glucose. Alpha- Hydrogen above the plane of the ring (OH below) and in Beta Hydrogen is below (with OH above). |
Storage polysaccharides. Which type of glucose are they formed from? | Starch and Glycogen. Alpha glucose. |
How are starch and glycogen structure related to their function? | Compact so can store a lot of energy. Branched chains so that enzymes can quickly release a lot of glucose. |
Type of bonds in a triglyceride | Ester bonds |
Difference between saturated and unsaturated fats. | Saturated fats DO NOT have any double bonds between the Carbon atoms (animal fats). Unsaturated fats have at least one double bond, this means they have a lower melting point (oils). |
Difference between triglycerides and phospholipids | Phospholipid- One of the fatty acid groups is replaced with a phosphate group. It has hydrophilic head and hydrophobic tail. |
Function of Cholesterol | Helps to strengthen cell membranes. Makes them less fluid and more rigid. |
Bond in the primary structure of proteins | Peptide bonds holding amino acids together. |
Bond in protein secondary structure and common shapes | Hydrogen Bonds. Alpha Helix and Beta pleated sheets. |
Bonds in tertiary protein structure | Ionic Bonds; Disulphide bonds; Hydrogen Bonds; Hydrophobic and Hydrophilic Interactions. |
Conjugated Protein; Prosthetic Group e.g. Haemoglobin | Conjugated protein means a proteins with a non-protein group attached. Non-protein group is called a prosthetic group. e.g. Iron in Haemoglobin. |
Role of Calcium | Transmission of nerve impulses. Important in blood clotting. |
Test for Proteins | Biuret test. Purple indicates protein, if no protein stays blue |
Test for Sugars | Bendicts test : Reducing sugars stays blue if no reducing sugar present. Goes green, yellow, orange, brick red as sugar concentration increases. If no change may be non-reducing sugar. Add Hydrochloric acid, heat, neutralise and test again. |
Formula for calculating Rf values in chromatography | Rf value = distance travelled by the spot divided by distance travelled by the solvent (measured from point of origin) |
Structure of a nucleotide | Pentose sugar and phosphate and a nitrogen containing base. |
4 types of bases in DNA; which ones pair together? | A, T, C, or G.
A with T and C with G. Held together by Hydrogen bonds. |
4 Bases in RNA | A, U, C or G (so NO T) |
Phosphorylated Nucleotides | A nucleotide with one or more phosphate groups added such as ADP or ATP. Energy is released from the phosphate bond when ATP is broken down to ADP. (ATP is made in respiration). |
How many bases code for each amino acid? How many amino acids are coded for in this DNA sequence? ATTCCGCCCTTTACG | 3 FOR ONE AMINO ACID.
5 coded for. |
What would this sequence be on messenger RNA?
CTACCAATACCTGG | GAUGGUUAUGGACC |
What is DNA semi-conservative replication? | Replication is to make an exact copy of itself. Semi-conservative is where one original strand is paired with a new strand to make a new double stranded DNA molecule. |
What type of molecule is an enzyme? How is it specific? | Globular Protein. Tertiary structure gives a specific 3D shape to the enzyme. |
What is formed when a substrate binds to an enzyme's active site? | An enzyme-substate complex. This then becomes an Enzyme-Product complex before products are released. |
What shape is a graph showing how enzyme rates of reaction are affected by temperature. Why is it this shape? | Shaped like a hill. Te optimum temperature is at the highest point. The rate then decreases past this point until it reaches zero when the enzyme is DENATURED. This is the same shape for pH |
1. Shape of graph showing effect of increasing enzyme concentration.
2. Shape of graph showing effect of increasing substrate concentration. | 1. Steep start then levels off as no more substrate is available.
2. Steep start then levels off as all the active sites are used. |
How do competitive inhibitors work? | They are a similar shape to the substrate. They compete with the substrate to bind to the active site but when they do no reaction takes place. |