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biological molecules Flashcards

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1
Q

Condensation Reactions

Condensation is the formation of ….

The byproduct of condensation reactions is ______

A

Condensation Reactions

Condensation is the formation of larger, biological molecules (polymers) from smaller molecules (monomers).

The byproduct of condensation reactions is water.

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2
Q

Formation

… (e.g. sugars) in an organism’s cells can form larger biological molecules (e.g. carbohydrates) that can be …

These biological molecules are important to …

A

Formation

Smaller, biological molecules (e.g. sugars) in an organism’s cells can form larger, molecules (e.g. carbohydrates) that can be used around the body.

These biological molecules are important to allow the organism to survive.

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3
Q

Condensation

Condensation is the reaction that …

The reaction releases _____ and ….

A

Condensation

Condensation is the reaction that forms large, biological molecules.

The reaction releases water and bonds the smaller components together into larger molecules.

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4
Q

Products of condensation

Condensation of amino acids produces ______.

Condensation of two ___________ produces disaccharides.

Many disaccharides form _____________.
Condensation of _________ and ___________ produces lipids.

A

Products of condensation

Condensation of amino acids produces proteins.

Condensation of two monosaccharides produces disaccharides.

Many disaccharides form polysaccharides.
Condensation of fatty acids and monoglycerides produces lipids.

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5
Q

Monoglycerides are … they are made up of …

A

Monoglycerides are a type of glyceride.

They are made up of glycerol and one fatty acid chain.

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6
Q

Carbohydrates are made of …

They are made from monosaccharides, which are … containing …

A

Carbohydrates are made of carbon, hydrogen and oxygen atoms.

They are made from monosaccharides, which are simple sugars containing three to seven carbon atoms.

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7
Q

Monosaccharides are simple _______.

Examples include: (3)

A

Monosaccharides are simple sugars.

Examples include:
Glucose.
Galactose (found in milk).
Fructose (found in fruit).

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8
Q

Glucose

Glucose is a __________ sugar that has the chemical formula __________.

Glucose is an important source of _________ in humans.

During cellular respiration, the energy released from glucose helps to make …

A

Glucose

Glucose is a hexose sugar that has the chemical formula C6H12O6.

Glucose is an important source of energy in humans.

During cellular respiration, the energy released from glucose helps to make adenosine triphosphate (ATP).

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9
Q

Alpha vs beta glucose

Alpha- and beta-glucose are _______. Isomers have the …

The carbon atoms are numbered from _____ and the OH (_________) groups are in a different orientation around ___.

A

Alpha vs beta glucose

Alpha- and beta-glucose are isomers. Isomers have the same molecular formula but a different arrangement of atoms in space.

The carbon atoms are numbered from 1 – 6 and the OH (hydroxyl) groups are in a different orientation around C1.

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10
Q

When two monosaccharides join via a _____________ reaction, they form a ______________.

When more than two monosaccharides join together, they form a …

A

When two monosaccharides join via a condensation reaction, they form a disaccharide.

When more than two monosaccharides join together, they form a polysaccharide chain.

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11
Q

Examples of disaccharides

Glucose + glucose → _________
Glucose + fructose → ________
Glucose + galactose → ________

A

Examples of disaccharides

Glucose + glucose → maltose.
Glucose + fructose → sucrose.
Glucose + galactose → lactose

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12
Q

Functions of disaccharides

Sucrose is …

Lactose is …

Lactose intolerance is a common problem where …

A

Functions of disaccharides

Sucrose is common table sugar.

Lactose is the sugar found in milk.

Lactose intolerance is a common problem where the body is unable to digest lactose.

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13
Q

Polysaccharides

Polysaccharides are made up of … by _____________ bonds

The chain may be __________ or ____________.
The chain may contain different types of _____________.

_________, _________ , _________ and ______ are examples of polysaccharides.

A

Polysaccharides

Polysaccharides are made up of two or more monosaccharides joined together by glycosidic bonds.

The chain may be branched or unbranched.
The chain may contain different types of monosaccharides.

Starch, glycogen, cellulose and chitin are examples of polysaccharides.

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14
Q

What are the products of the hydrolysis of sucrose?

A

What are the products of the hydrolysis of sucrose?

Fructose and glucose

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15
Q

Reducing sugars

All ________________ are reducing sugars.
E.g. …(3)

Some disaccharides are reducing sugars.
E.g. _________ and _________

A

Reducing sugars

All monosaccharides are reducing sugars.
E.g. Glucose, galactose and fructose.

Some disaccharides are reducing sugars.
E.g. Lactose and maltose.

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16
Q

Test for reducing sugars

Benedict’s solution can be reduced by reducing sugars.

Benedict’s solution is a clear blue liquid that changes _________ and gives a ___________ depending on how much it is reduced.

Step 1: …
Step 2: …
Step 3: …
Step 4: …

A

Test for reducing sugars

Benedict’s solution can be reduced by reducing sugars.

Benedict’s solution is a clear blue liquid that changes colour and gives a precipitate depending on how much it is reduced.

Step 1: Place 2 ml of the substance into a clean test tube (substance must be in liquid form).
Step 2: Add 10 drops of Benedict’s solution.
Step 3: Place in a boiling water bath for 3-5 minutes
Step 4: Observe for color change in the solution of test tubes or precipitate formation

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17
Q

Structure of Glucose

Glucose is a ______________. It is a hexose _______, which means that …

A

Structure of Glucose

Glucose is a monosaccharide. It is a hexose sugar, which means that each molecule contains six carbon atoms.

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18
Q

Results of the Benedict’s test

Blue solution → …
Green/yellow precipitate → …
Orange/red precipitate → …
Brick red precipitate → …

A

Results of the Benedict’s test

Blue solution → no reducing sugar.
Green/yellow precipitate → traces of reducing sugar.
Orange/red precipitate → moderate amounts of reducing sugar.
Brick red precipitate → large amount of reducing sugar.

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19
Q

Non-reducing sugars

Non-reducing sugars will show a _________ result to the Benedict’s test.

… is needed to determine if non-reducing sugar is present.

__________ is a non-reducing sugar. It is a disaccharide made up of glucose and fructose joined by a _________ bond.

A

Non-reducing sugars

Non-reducing sugars will show a negative result to the Benedict’s test.

A second test is needed to determine if non-reducing sugar is present.

Sucrose is a non-reducing sugar. It is a disaccharide made up of glucose and fructose joined by a glycosidic bond.

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20
Q

Test for non-reducing sugars

Step 1 - hydrolyse the sample into reducing sugars: …
Step 2: …
Step 3: …

The result will now be _________ if a non-reducing sugar is present.

If the solution remains blue, then …

A

Test for non-reducing sugars

Step 1: to hydrolyse the non-reducing sugar, Add 1cm cubed of dilute HCl acid to 2cm cubed of the sample. Mix and boil the mixture for about 2 – 3 minutes. Allow the mixture to cool and then..
Step 2: Neutralise the solution by adding sodium hydrogen carbonate. (Baking soda) until the solution is slightly alkaline.
(Benedict’s reagent will only work in an alkaline environment, so check with a blue litmus paper to detect when the solution turns alkaline.)
Step 3: Repeat the Benedict’s test.

The result will now be positive if a non-reducing sugar is present.

If the solution remains blue, then no sugar is present.b

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21
Q

Types of sugars

Reducing sugars

All monosaccharides
E.g.
E.g.
E.g.

Some disaccharides
E.g.
E.g.

Non-reducing sugars
E.g.

A

Types of sugars

Reducing sugars

All monosaccharides
E.g. glucose
E.g. fructose
E.g. galactose

Some disaccharides
E.g. lactose
E.g. maltose

Non-reducing sugars
E.g. sucrose

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22
Q

Starch

Starch is a polysaccharide formed by ____________ reactions of ____________ molecules and a common …

A

Starch

Starch is a polysaccharide formed by condensation reactions of alpha-glucose molecules and is a common storage compound

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23
Q

Functions of starch

Starch is the main energy storage material in _______.

Starch is stored in the ______ of plants.

Starch is broken down into _______ by plants when …

Starch can act as a source of _______ for …

A

Functions of starch

Starch is the main energy storage material in plants.

Starch is stored in the seeds of plants.

Starch is broken down into glucose by plants when they need more energy.

Starch can act as a source of food for humans and animals.

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24
Q

Features of starch

Starch does NOT change the … in a cell because it’s insoluble in water.

A

Features of starch

Starch does NOT change the water potential in a cell because it’s insoluble in water.

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25
Q

Iodine test

A common test for the presence of _______, particularly in food testing, is to add iodine solution.

Iodine solution is made by …

Step 1: …

Step 2: …

If starch is present, the solution will change colour from …

A

Iodine test

A common test for the presence of starch, particularly in food testing, is to add iodine solution.

Iodine solution is made by mixing iodine and a solution of potassium iodide.

Step 1: Place a small sample into the dimple of a spotting tile or to a boiling tube.

Step 2: Add a few drops of iodine solution and observe any colour change.

If starch is present, the solution will change colour from orange → blue-black.

26
Q

Types of Starch

A

Types of Starch

Amylose

Amylopectin

27
Q

Types of Starch

Amylose
Unbranched or branched
Good for …

Amylopectin
Unbranched or branched
Good for …

A

Types of Starch

Amylose
Unbranched
Good for energy storage

Amylopectin
Branched
Good for quick energy release

28
Q

Glycogen

Glycogen is formed by ______________ reactions of ____________ molecules and is the main energy storage material in __________.

It can be thought of as the animal equivalent of _______

A

Glycogen

Glycogen is formed by condensation reactions of alpha-glucose molecules and is the main energy storage material in animals.

It can be thought of as the animal equivalent of starch.

29
Q

Function of glycogen

Glycogen is a highly _________ molecule, similar to ____________ (a form of starch).

When animals need to release energy, glycogen’s highly branched structure means that …

A

Function of glycogen

Glycogen is a highly branched molecule, similar to amylopectin (a form of starch).

When animals need to release energy, glycogen’s highly branched structure means that glucose can quickly be released.

30
Q

Glycogen in the human body

Glycogen is a good storage molecule because it is so _________

When blood glucose levels decrease, glycogen is … This is called glycogenolysis

A

Glycogen in the human body

Glycogen is a good storage molecule because it is so compact.

When blood glucose levels decrease, glycogen is broken down to release glucose. This is called glycogenolysis

31
Q

When blood glucose levels decrease, glycogen is broken down to release glucose. This is called _____________

A

When blood glucose levels decrease, glycogen is broken down to release glucose. This is called glycogenolysis

32
Q

Cellulose is the major component of cell walls in _________

A

Cellulose is the major component of cell walls in plants

33
Q

Structure of cellulose

Cellulose is a … of _____-________

Beta-glucose molecules are linked by glycosidic bonds to form …

____________ are strong fibres that are made of many cellulose chains that are held together by _________ bonds.

A

Structure of cellulose

Cellulose is a long chain of beta-glucose.

Beta-glucose molecules are linked by glycosidic bonds to form linear cellulose chains that are unbranched.

Microfibrils are strong fibres that are made of many cellulose chains that are held together by hydrogen bonds.

34
Q

Function of cellulose

Cellulose is the most abundant natural _________.

The cell walls of plant cells are mostly made of __________.

These cell walls offer ____________ support because of the strength of the ________ fibres that they are made of.

A

Function of cellulose

Cellulose is the most abundant natural polymer.

The cell walls of plant cells are mostly made of cellulose.

These cell walls offer structural support because of the strength of the microfibril fibres that they are made of.

35
Q

Digestion of cellulose

Cellulose cannot be broken down by human …

___________, such as cows and horses, are able to digest plant material rich in cellulose.

A

Digestion of cellulose

Cellulose cannot be broken down by human digestive enzymes.

Herbivores, such as cows and horses, are able to digest plant material rich in cellulose.

36
Q

Triglycerides are …

A

Triglycerides are a type of lipid that are mainly used as energy storage molecules.

37
Q

Formation of triglycerides

Triglycerides are formed by …

Ester bonds form …

One water molecule is released per …

So, three molecules of water are released per …

A

Formation of triglycerides

Triglycerides are formed by the condensation of one molecule of glycerol and three molecules of fatty acid.

Ester bonds form between the glycerol and the fatty acid chains.

One water molecule is released per ester bond.

So, three molecules of water are released per triglyceride formed.

38
Q

Structure of fatty acids

Fatty acids have long ‘tails’ made of a … with ___ carbon atoms.

The hydrocarbon tail is variable but …

Glycerol links to …

A

Structure of fatty acids

Fatty acids have long ‘tails’ made of a chain of hydrocarbons with 4-36 carbon atoms.

The hydrocarbon tail is variable but most fatty acids contain 12-18 carbons.

Glycerol links to the central carbon atom on fatty acids.

39
Q

Types of fatty acids

The three fatty acids in the triglyceride may be similar or dissimilar.

Fatty acids may be …

Some fatty acids have names that come from their origin.
E.g. _________ is a saturated fatty acid that comes from the palm tree.

A

Types of fatty acids

The three fatty acids in the triglyceride may be similar or dissimilar.

Fatty acids may be saturated or unsaturated.

Some fatty acids have names that come from their origin.

E.g. Palmitic acid is a saturated fatty acid that comes from the palm tree.

40
Q

Formation of Triglycerides

Triglycerides are formed by …

Three molecules of water are released per triglyceride formed:

A

Formation of Triglycerides

Triglycerides are formed by the condensation of one molecule of glycerol and three molecules of fatty acid.

Three molecules of water are released per triglyceride formed:

  • 1 molecule of glycerol.
  • 3 molecules of fatty acid.
  • 3 molecules of water.
41
Q

Functions of Triglycerides

The structures of triglycerides are related to their functions as molecules responsible for …

A

Functions of Triglycerides

The structures of triglycerides are related to their functions as molecules responsible for storing energy.

42
Q

Triglycerides in energy release

Chemical energy is stored in …

So, lots of energy is released when …

A

Triglycerides in energy release

Chemical energy is stored in the fatty acid hydrocarbon tails.

So, lots of energy is released when triglycerides are broken down.

43
Q

______ contain lots of energy

___________ contain half the amount of energy per gram as lipids do.

A

Lipids contain lots of energy

Carbohydrates contain half the amount of energy per gram as lipids do.

44
Q

Triglycerides repel water

Triglycerides are ______ in water because …

This means that … is NOT affected by triglycerides.

This is important because if triglycerides didn’t repel water, … This would make the cells …

A

Triglycerides repel water

Triglycerides are insoluble in water because the fatty acid tails are hydrophobic.

This means that the cell’s water potential is NOT affected by triglycerides.

This is important because if triglycerides didn’t repel water, the water would enter the cell through the process of osmosis. This would make the cells swell up.

45
Q

Lipid droplets

In cells, the _______ triglycerides crowd together as droplets because …

A

Lipid droplets

In cells, the insoluble triglycerides crowd together as droplets because the hydrophobic fatty acid tails face inwards.

46
Q

Phospholipids are a type of ____ that …

They are the main component of … and are responsible for …

A

Phospholipids are a type of lipid that forms a bilayer.

They are the main component of cell membranes and are responsible for controlling what goes into and out of cells.

47
Q

Structure of phospholipids

Phospholipids and triglycerides are quite similar. They are both composed of …

The main difference is that one of the three hydrophobic fatty acid tails is ….

This means that a phospholipid molecule has a __________ and _________ part.

This kind of molecule is called an _________ molecule.

A

Structure of phospholipids

Phospholipids and triglycerides are quite similar. They are both composed of fatty acid chains attached to glycerol
.
The main difference is that one of the three hydrophobic fatty acid tails is replaced by a hydrophilic phosphate group in phospholipids.

This means that a phospholipid molecule has a hydrophobic and hydrophilic part.

This kind of molecule is called an amphipathic molecule.

48
Q

Hydrophobic tail

Phospholipids have ___ fatty acid chains.

The ___ fatty acid chains in phospholipids are _________ and cannot …

In membranes, the hydrophobic fatty acid tails face …

This means that … can’t easily pass through the membrane.

A

Hydrophobic tail

Phospholipids have two fatty acid chains.

The two fatty acid chains in phospholipids are hydrophobic and cannot interact with water.

In membranes, the hydrophobic fatty acid tails face inwards in the bilayer.

This means that water-soluble substances can’t easily pass through the membrane.

49
Q

Hydrophilic head

The modified phosphate group in phospholipids is _________ and can …

In membranes, the hydrophilic phosphate group faces ….

A

Hydrophilic head

The modified phosphate group in phospholipids is hydrophilic and can interact with water.

In membranes, the hydrophilic phosphate group faces the outside.

50
Q

What is the approximate maximum magnification of a light microscope?

A

What is the approximate maximum magnification of a light microscope?

1,500x

51
Q

Types of microscopes:

Electron microscope
Use a …

Light microscope
Use a …

A

Types of microscopes:

Electron microscope
Use a beam of electrons.

Light
microscope
Use a beam of light.

52
Q

What is a glycerine?

A

What is a glycerine?

A fatty acid Ester of glycerol

E.g. 
Caprylic acid.
Capric acid.
Lauric acid.
Myristic acid.
Palmitic acid.
Stearic acid.
53
Q

Saturated Fatty Acids

A fatty acid is saturated if …

A

Saturated Fatty Acids

A fatty acid is saturated if there are only single bonds between carbon atoms in the hydrocarbon chain.

54
Q

Structure of saturated fatty acids

Carbon atoms are NOT …

In saturated fatty acids, the number of hydrogen atoms attached to the carbon skeleton is ___________. This means that …

A

Structure of saturated fatty acids

Carbon atoms are NOT joined by double bonds in saturated fatty acids.

In saturated fatty acids, the number of hydrogen atoms attached to the carbon skeleton is maximised. This means that the fatty acid is saturated.

55
Q

Function of saturated fatty acids

Saturated fats are _______ at room temperature and usually of …

Saturated fats are linked to …

Examples of foods with a high proportion of saturated fats include …

A

Function of saturated fatty acids

Saturated fats are solid at room temperature and usually of animal origin.

Saturated fats are linked to an increased risk of cardiovascular disease in humans.

Examples of foods with a high proportion of saturated fat include cream, cheese, butter, other whole milk dairy products and fatty meats.

56
Q

Unsaturated fats

When the hydrocarbon chain contains at least … bond, the fatty acid is unsaturated.

A

Unsaturated fats

When the hydrocarbon chain contains at least one double bond, the fatty acid is unsaturated.

57
Q

Structure of unsaturated fats

The main difference between saturated and unsaturated fatty acids is …

Unsaturated fatty acids have ____ or more double bond between carbon atoms in the hydrocarbon chain.

… are examples unsaturated fatty acids.

A

Structure of unsaturated fats

The main difference between saturated and unsaturated fatty acids is their hydrocarbon tails.

Unsaturated fatty acids have one or more double bond between carbon atoms in the hydrocarbon chain.

Cooking oils are examples unsaturated fatty acids.

58
Q

Unsaturated fats

________ at room temperature

Double bonds ‘kink’ the carbon chain so
…

This explains why they remain ______ at room temperature.

A

Unsaturated fats

Liquid at room temperature

Double bonds ‘kink’ the carbon chain so unsaturated fats cannot pack together tightly.

This explains why they remain liquid at room temperature.

59
Q

There are two types of fatty acids:

A

There are two types of fatty acids:

Saturated - no double bonds
Unsaturated - one ore more double bonds

60
Q

Emulsion Test

An emulsion is when …

The emulsion test returns a positive result if …

A

Emulsion Test

An emulsion is when small droplets of a substance are suspended in another solution.

The emulsion test returns a positive result if a sample contains a lipid.

61
Q

Emulsion test/test for presence of a lipids

1)

2)

3)

4)

A

Emulsion test/test for presence of a lipids

1) Add sample
Place sample in a boiling tube with ethanol.

2) Shake solution
Shake well and leave upright for 2-3 minutes.

3) Transfer solution
Pour the solution into a boiling tube containing distilled water.

4) Observe results
If a lipid is present, a white and milky layer will form.

biology a level (14 decks)

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