IB SL - Molecular Biology
Terms in this set (83)
Four most common elements?
Carbon, Hydrogen, Oxygen and Nitrogen
What are organic compounds?
Compounds that contain carbon
What are the exclusions to carbon organic compounds?
Carbonates, hydrogen carbonates and oxides of carbon
What are the four main groups of organic compounds?
Carbohydrates, lipids, proteins and nucleic acids
What is urea?
An organic compound produced by living organisms and can be artificially synthesised.
Example of a hydrophilic substance?
Sugars and salts
Example of hydrophobic substances?
A molecule that is part hydrophobic and part hydrophilic
Example of amphiphatic substance?
What type of molecule is water?
What charge does an oxygen atom have?
What charge does an hydrogen atom have?
What are the bonds in water called?
What causes the attraction of hydrogen bonds?
What does water's polarity allow it to do?
To dissolve other polar molecules such as sugars
What do you call water's attraction to other molecules?
What are water's key characteristics?
High specific heat
High latent heat of vaporisation
What is high specific heat?
It can store a large amount of heat
What is high latent heat of vaporisation?
It takes a lot of energy to turn liquid water into water vapour.
What percentage of blood is plasma?
What percentage of plasma is water?
Water's use as a heat transporter?
Water's high specific heat allows heat to be transported from a hotter part of the body to a cooler part.
Water's suitability as a habitat?
Water's high specific heat makes it a stable habitat as it requires a lot of heat energy to heat water and loses heat slowly.
Waters's use as a coolant?
Water's high specific heat and latent heat of vaporisation help in the formation of sweat to cool the body.
Water's use as a transporter in blood?
As a polar solvent substances such as sugars amino acids readily dissolve and non-polar substances such as fats are transported as lipoproteins.
Water's use as a transporter in plants?
Adhesion attracts water molecules to the surface of the xylem vessel, the small channel size creates high adhesive forces.
Cohesion between water molecules pulls the molecules up the xylem.
Name four carbohydrates
Sugars, starch, glycogen and cellulose
What type of structure is starch?
Position of hydroxyl group on carbon 1 in Alpha-D-glucose?
Below the ring
Position of hydroxyl group on carbon 1 in Beta-D-glucose?
Above the ring
Pattern of position of hydroxyl in Alpha glucose?
Down Down Up Down
Pattern of position of hydroxyl in Beta glucose?
Up Down Up Down
Examples of monosaccharides?
Glucose, Galactose, Fructose
Which process joins monosaccharides?
Examples of disaccharides?
Maltose, lactose, sucrose
Glucose + Glucose =
Glucose + Galactose =
Glucose + Fructose=
Example of polysaccharides?
Starch, cellulose, glycogen
What are starch, cellulose and glycogen all made up of?
What glucose forms cellulose?
What glucose forms starch?
What glucose forms glycogen?
Describe the structure of Cellulose
Strong, straight, unbranched chains joined by 1-4 linkage
What are the two forms of starch?
Amylose and amylopectin
Describe the structure of amylose
Amylose is unbranched
Describe the structure of amylopectin
Slightly branched using 1-6 linkages
General structure of Starch?
Coiled and insoluble
Describe the structure of glycogen
Very branched using 1-6 linkages and insoluble
Function of cellulose
Cell wall of plant cells
Porous and allows water to flow through it
Function of starch
Energy storage molecule in plants
Function of glycogen
Energy storage molecule in animals
Found in liver and skeletal muscle cells.
Why is cellulose so strong?
It has large numbers of hydrogen bond crosslinks between strands.
Three examples of lipids
Triglycerides, phospholipids and steroids
What are triglycerides composed of?
Glycerol and three fatty acids
How are triglycerides formed?
What is the structure of a saturated fatty acid?
They have no double bonds between carbons
What is the structure of an unsaturated fatty acid?
They have one or more double bonds between carbons
What is a mono-unsaturated fatty acid?
A fatty acid with one double bond
What is a polyunsaturated fatty acid?
A fatty acid with two or more double bonds
What does cis mean?
The hydrogen atoms are each on the same side on each side of the double bond
What does trans mean?
The hydrogen atoms are on opposite sides on each side of the double bond
What is the structure of a phospholipid?
It is similar to a triglyceride but the third fatty acid tail is replaced with a phosphate group.
Where are phospholipids found?
Why are carbohydrates a good energy store?
Easily built up for storage
Easily broken down for quick energy release
What is glucose stored as in animals?
What is glucose stored as in plants?
What are carbs converted to in plants and animals when energy is required?
Why are lipids a good energy store?
Twice as much energy released per gram than carbs
More efficient as an energy store
Why do metabolic pathways improve the efficiency of lipids as an energy store?
They build up and break down more complex and therefore slower
Why does the hydrophobic trait of lipids improve its efficiency as an energy store?
Less mass is taken up storing water
What are lipids converted to when energy is required?
Glycerol and fatty acids
What can trans fats and unsaturated fats lead to?
High levels of LDL and increased risk of coronary heat disease - insufficient evidence for a link
What is condensation?
The building up of monomers - water is released
What is hydrolysis?
The breaking down of polymers
What is built up through frequent condensation reactions with carbohydrates?
What is built up through frequent condensation reactions with amino acids?
Polypeptides - this is translation and occurs in the ribosome
What is the equation for BMI?
Mass in kg / (Height in m)²
What are the units for BMI?
What is a normal BMI?
What is an obese BMI?
What chart is used to measure BMI?
What type of molecule is water?