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Biology > 2.2 Biological molecules > Flashcards

2.2 Biological molecules Flashcards

1
Q

What is cellulose?

A

Cellulose is found in the cell walls of plant cells and gives structure and support. It is made of B-glucose monomers that form long straight lines. Hydrogen bonds form between glucose molecules on adjacent strands to provide strength to the cells.

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2
Q

What is the structure of cellulose?

A

Cellulose is a linear polymer made up pf glucose units linked by B-1,4-glycosidic bonds.

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3
Q

What is cellulose used for?

A

Cellulose is an excellent material for plant cell wall.
Microfibrils and microfibrils have very high tensile strength. Microfibrils are stronger than steel wire of the same diameter.
They criss-cross the wall for extra strength.

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4
Q

What are the properties and functions of cellulose?

A

structural carbohydrate in plant cell walls.
Hydrogen bonds between cellulose chains give strength to cell walls.

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5
Q

What are the properties and functions of glycogen?

A

Energy storage in animals.
Insoluble.
Does not affect the water potential of the plant.
Branches can easily broken so that glucose can be used in respiration.

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6
Q

What are the properties and functions of starch?

A

Energy store in plants.
Insoluble.
Does not affect the water potential of the plant.
Branches can be easily broken so that glucose can be used in respiration.

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7
Q

What are triglycerides?

A

They are a type of lipid consumed in our diet that we use as an energy source. They are digested in our small intestines into fatty acids and glycerol.

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8
Q

What are the products of triglycerides used for?

A

They are used by the body’s cells to produce phospholipids - a part of a cell’s plasma membrane. They can also be used to store fat in the body as triglycerides.

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9
Q

What is the structure of triglycerides?

A

Glycerol backbone with three fatty acid chains.

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10
Q

How do triglycerides synthesis?

A

Condensation reaction forms three ester bonds between the fatty acids and glycerol.

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11
Q

What are amino acids?

A

Amino acids are the molecules that make up proteins.
There are 20 different amino acids that make up proteins and all of them have a similar structure.

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12
Q

What are amino acids made of?

A

All amino acids are made out of carbon, hydrogen, oxygen and nitrogen, but some also contain sulphur.

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13
Q

How do amino acids bond together?

A

A hydroxyl group from the carboxyl group on one amino acid and a hydrogen from the amino acid group on the other amino acid are removed and form a water molecule. A peptide bond forms between the carboxyl and amino groups. The amino acids are bow a dipeptide. This is a condensation reaction.

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14
Q

How do amino acids break down?

A

The peptide bond can be broken by the addition of a water molecule. The hydroxyl group is added to the carboxyl group of the first amino acid and the hydrogen is added to the amino group of the second amino aid. This is a hydrolysis reaction.

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15
Q

What is quantitative data?

A

Quantitative refers to data or information that is measurable or expressed in numerical form.

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16
Q

What is an example of quantitative data?

A

Colorimetry

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17
Q

What is colorimeter?

A

A colorimeter is a machine that measures the absorbance of filtered light through a coloured solution. The higher the absorbance, the higher the concentration of the solution.

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18
Q

How does a colorimeter work?

A

The colorimeter can calculate the amount of light absorbed by the solution. This is shown on a digital display. measuring more than one concentration allows a calibration curve to be plotted.

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19
Q

How do you do colorimetry?

A

A sample of distilled water is placed into the colorimeter to set it to 0.00. Samples of known concentration are added to the colorimeter. The filter in the colorimeter is changed to the colour that would be best absorbed by the sample. The absorbance of each sample is measured. The absorbances of unknown samples are then measured and the concentration is worked out using the calibration curve.

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20
Q

What is a biosensor?

A

A device that converts the compound into a electrical signal that is proportional to the amount of compound.

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21
Q

What are the properties of lipids?

A

They are large, organic molecules, non-polar, insoluble in water and soluble in alcohol. They contain fatty acids which are long chains of carbon and hydrogen.

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22
Q

What are the uses of triglycerides

A

Energy source - used by prokaryotes and eukaryotes in respiration to produce ATP.
Energy storage - mammals store it in adipose tissue.
Protection - body organs surrounded by fat which protects them.
Insulation - Animals that live in cold climates have a layer of adipose called blubber.
Buoyancy - aquatic animals use their blubber to help them float as triglycerides are less dense than water.

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23
Q

What are the uses of phospholipids?

A

Main component of the plasma membrane, form a bilayer.

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24
Q

What is the phospholipid bilayer?

A

It acts as a partially permeable membrane, allowing only small or non-polar molecules into the cell. This is because the phosphate head is hydrophilic and attracts water, whereas the lipid tail is hydrophobic and repels water.

25
Q

What is the use of cholesterol?

A

It adds stability to plasma membranes. Animals that live in cold regions have more cholesterol in their membranes to prevent them from freezing.

26
Q

What is the structure of water?

A

1 oxygen (+) and 2 hydrogen atoms (-).
It is a dipolar molecule meaning it contains 1 negative and 1 positive charge.

27
Q

What are the properties of water?

A

Thermal stability, Forms a liquid, Low density of ice, Surface tension, Cohesion, Solvent, Metabolic and Transparency.

28
Q

What is the benefit of thermal stability of water?

A

Stable environment for aquatic organisms.

29
Q

What is the benefit of water forming a liquid?

A

Transport medium in animals and pants.

30
Q

What is the benefit of low density in ice?

A

Ice floats in water and insulates the water below.

31
Q

What is the benefits of surface tension of water?

A

Small animals can move across the surface of the water.

32
Q

What is the benefit of cohesion of water?

A

Water molecules form a strong water column that moves up the xylem in plants.

33
Q

What is the benefit of water being a solvent?

A

Chemicals dissolve in water in the cytoplasm can take part in reactions.

34
Q

What is the benefit of water being metabolic?

A

Water is used to break bonds in hydrolysis and make bonds in condensation reactions.

35
Q

What is the benefit of water being transparent?

A

Water allows light to move through it so aquatic plants can photosynthesise.

36
Q

How are hydrogen bonds formed in water?

A

Hydrogen bonds can form between the oxygen atom of one water and a hydrogen of another water (cohesion).

37
Q

Why is it hard to heat and cool water?

A

The molecules are held together quite tightly by hydrogen bonds. It takes energy to break these bonds and so the high heat capacity provides thermal stability, making water a stable habitat.

38
Q

What are biological molecules made of?

A

They are made of a small selection of elements (C,H,O,N,S,P) and sometimes inorganic ions (Fe2+, Zn2+, Mg2+) as part of a biological process.

39
Q

What is a monomer?

A

A single molecule, e.g. a molecule of glucose.

40
Q

What is a polymer?

A

A chain of monomer bonded together, e.g. amylose is a polymer of glucose monomers.

41
Q

How are monomers bonded together?

A

Condensation reaction.

42
Q

How are monomers broken apart?

A

Hydrolysis reaction.

43
Q

How is a condensation reaction formed?

A

A covalent bond is formed between two monomers by the removal of OH from one monomer and H from the other.

44
Q

How is a hydrolysis reaction formed?

A

A covalent bond between two monomers is broken by the addition of a water molecule. OH is added to one monomer and H to the other.

45
Q

What is a monosaccharide?

A

It is the simplest unit of carbohydrates.

46
Q

What is a disaccharide?

A

They are 2 monosaccharides bound together by a glyosidic bond.

47
Q

How are glyosidic bonds formed?

A

Glyosidic bonds form between 2 monosaccharides using a condensation reaction. The same is used to add monosaccharides to polysaccharide.

48
Q

How is a glyosidic bonded broken down?

A

A molecule of water is added to break down the glyosidic bond. This is a hydrolysis reaction.

49
Q

What is the structure of starch?

A

Starch is made of 2 different polysaccharides - amylose ad amylopectin. They are both made of a-glucose monomers but have a different structure.

50
Q

What is the structure of glycogen?

A

Glycogen is made of a-glucose monomers and has a similar structure to amylopectin.

51
Q

What are carbohydrates made of?

A

They are made of polymers which are made of many similar, smaller molecules bonded together.

52
Q

What is a protein?

A

They are big complicated molecules, made of 4 different levels.

53
Q

What is the primary structure of a protein?

A

This is the sequence of amino acids in the polypeptide chain. A change in one of the amino acids may change the structure of the whole protein.

54
Q

What is the secondary structure of a protein?

A

Hydrogen bonds form between nearby amino acids in the chain. This makes it automatically coil into an alpha helix or fold into a beta pleated sheet.

55
Q

What is the tertiary structure of a protein?

A

The coiled or folded chain of amino acids is often coiled and folded further. More bonds form between different parts of the polypeptide chain. For some proteins made from a single polypeptide chain, this is their final 3D structure.

56
Q

What is quaternary structure of a protein?

A

Some proteins are made of several different polypeptide chains held together by bonds. The quaternary structure is the way these polypeptide chains are assembled together.

57
Q

What is the bond between primary structure of proteins?

A

Held together by the peptide bonds between amino acids.

58
Q

What is the bond between secondary structure of proteins?

A

Held together by hydrogen bonds.

59
Q
A

Biology (25 decks)

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