C3 Flashcards
Define polar
The molecule has regions of positive and negative charge
Water is an example of a _____ molecule with a _____ boiling point
Polar, high
What makes water small, light and liquid at room temperature
The H bonds within the molecule and between molecules
What does it mean by water has a high specific latent heat?
It takes a lot of energy to increase temperature of water and turn it into gas
Ice is ____ dense than water, making it float, and creating an insulating layer.
Less
Water acts as a _____ for solutes in an organism and therefore is an efficient ________ _______ for chemical reactions.
Solvent, Transport medium
What is capillary action and give one example of where it occurs
The movement of water up a narrow tube against the force of gravity, e.g., in the xylem
Glucose molecules are ______ and _____ in water. Thus is Important as glucose needs to be dissolved in the cytology of the cell.
Polar, soluble
What is released when 2@ glucose molecules undergo a condensation reaction
Water
Fructose + glucose =
Galactose + glucose =
Sucrose
Lactose
What bond is created when 2 glucose molecules join
Glycosidic
Glucose produced by photosynthesis, is stored as ___ which can be either amylose or ______
Starch, amylopectin
Describe the properties of amylose as a store of glucose
Only 1,4 glycosidic bonds between alpha glucose monomers. Angle of the bond means they twist and form a helix structure, which is stabilized by simple hydrogen bonds. Making the molecule less soluble, and more compact.
Describe the properties of amylopectin as a chemical store for glucose
Both 1,6 and 1,4 glycosidic bonds, has a branched structure. Insoluble, very compact. Ideally suited to its function.
What is the main chemical energy store in humans? And how does it differ from that of plants.
Very similar to the starch polysaccharide amylopectin. Just more branched and therefore more compact, meaning more space to be stored.
Branching of glycogen means that there are many free ends for glucose to be added or removed.
Why is it important that humans have a better chemical energy store than plants?
Plants are immobile. Humans are mobile and so need more energy.
Cellulose has what monomers?
B glucose.
Why does cellulose build a straight chain rather than a branched one?
Cellulose has B monomers, so every other monomer has to be flipped 180 degrees to alllow the hydroxyl groups to be close enough to react
Cellulose molecules make __ bonds with each other, forming microfibrils, these react producing macro fibrils, which then form ____
H, FIBRES
Cellulose is hard to break down, this is necessary for a good _______ system
Digestive
Explain how Benedict’s test is used to test for reducing sugars and explain a positive result
- Please the sample to be tested in the boiling tube. If it’s not liquid grind or blend in water before hand
- Add an equal volume of Benedict reagent
- Heat the mixture in a boiling water bath for five minutes
- If reducing sugars a present it will go from light blue to brick red
Explain how Benedict’s test can be adapted to test for non reducing sugars.
Firstly, do Benedict’s Normally, results should be negative, then mix solution with hydrochloride acids and do the test again, it should then produce a positive test.
What is the test used for starch
Iodine
Explain the steps of testing for starch
- A few drops of iodine should be dissolved into potassium iodide
- They should then be mixed with a sample
- If the solution changes from yellow to black starch is present
What is the advantage of using reagent strips.
With the combination of a reagent strip and a color coded chart, we can determine the exact concentration of sugar.
Explain colorimity as a quantitative method to determine sugar concentration
The more concentrated solution the more light it will absorb and then less light it will transmit, this can be used to calculate the concentration of reducing sugar present
Lipids are commonly known as fats and oils. Fats are ____ at room temperature. Oils are ____ at room temperature, however, oils and _____ do not mix as they are not _____ soluble.
Solid, Liquid, water, water
A tryglyceride is a type of lipid composed of….
3 fatty acids attached to a glycerol molecule
When does esterfication occur
When 3 ester bonds are formed and 3 water molecules are released when bonding glycerol and 3 fatty acids.
What is a saturated fatty acid
A fatty acid that has no double bonds between C atoms. Because the C atoms have already formed the max amount of bonds with H atoms.
What is an unsaturated fatty acid
A fatty acid with double bonds between C atoms. Just one double bond means it is monounsaturated. 2 or more means it is polyunsaturated. The presence of these bonds means the molecule cannot pack so closely together, making them liquid at room temperature, so unsaturated fatty acids are oils.
Unsaturated fats tend to be more ____ to humans than Saturated fats. As excess _____ may link to coronary heart disease.
Healthy, Saturated
Describe the structure of a phospholipid
Modified triglycerides, only 2 fatty acid chains, contain and inorganic phosphate group. They are soluble in water. They have a hydrophilic head, and a hydrophobic tail, making them effective membrane components.
What is an individual nucleotide made up of
A pentose sugar, A phosphate group, A nitrogenous base.
How does a phosphodiester bond occur between nucleotides
Phopshate group or the 5th carbon in the pentose sugar forms a covalent bond with the hydroxyl group of the pentose sugar in the adjacent nucleotide,
What the pyramdines
Smaller bases, single carbon ring, T and C
What are the purines
Larger bases, which contain double carbon rings. A and G
DNA varies in length from a few nucleotides to millions. It is made up of two strands of _____________ coiled into a _____. The 2 strands are held together by ______ bonds between the bases.
Polynucleotides coiled into a helix. Held together by hydrogen bonds between the nucleotides.
Each strand of DNA has a phosphate group (5’) and a ___ (_’) at each end. They are arranged so they run in opposite directions, they are said to be ____________
OH 3’, said to be antiparralel
Explain transcription phase of protein synthesis
DNA converted into mRNA.
- One of the original strands contains the code for the protein to be synthesised. This is the sense strand and runs 5’ to 3’
- The other strand is called antisense and acts as as a template strand. This runs 3’ to 5’
- Free RNA nucleotides join to the antisense strand. Phosphodiester bonds are formed by RNA polukerase .
- MRNA leaves the antisense strand as the DNA double helix is rejoined. The mRNA now leaves for translation.
In eukaryotic cells, ______ are made up of 2 subunits. One large and one small. They are composed of equal amounts of protein and form rRNA.
Ribosomes
Why is ribosomal RNA important in translation
Maintains the structural stability of the protein synthesis sequence. Plays a biochemical role in catalysing the reaction.
