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(A Level) Biology > Topic 1 - Saccharides + Triglycerides 1.12 To 1.16 > Flashcards

Topic 1 - Saccharides + Triglycerides 1.12 To 1.16 Flashcards

1
Q

What are monosaccharides

A

The monomers of carbohydrates (sugars)

They form glycosidic bonds with each other to form polysaccharides

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2
Q

What is a hexose monosaccharide

A

A monosaccharide containing 6 carbons.
It has the formula

C6 H12 O6

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3
Q

What is the difference between alpha glucose and beta glucose (structure)

A

In alpha Glucose the H group is above Carbon 1 and the OH is below C1

In beta glucose the OH group is above C1 and the H group is below C1

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4
Q

What is the only structural difference between beta glucose and galactose

A

In beta glucose the H group is above C4 and the OH group is below

In galactose the OH group is above C4 and the H group is below

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5
Q

How is the structure of Fructose different from glucose and galactose

A

Fructose contains two CH2 OH groups

Because of this it has a pentagonal structure (but is still a hexose sugar)

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6
Q

What are glucose, fructose and galactose

A

They are monosaccharides

They are hexose sugars

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7
Q

What is a disaccharide

A

The molecule formed when two monosaccharides form glycosidic bons with each other

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8
Q

What type of reaction makes disaccharides / polysaccharides

A

Condensation reactions

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9
Q

How much water is produced when two hexose monosaccharides form a disaccharide

A

1 H20

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10
Q

What is the formula of a disaccharide formed by hexose monosaccharides

A

C12 H22 O 11

(C6 H12 O6 ×2) - ( 1 H20)

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11
Q

What is maltose

A

A disaccharide formed when two alpha glucose molecules form an alpha 1-4 glycosidic bond

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12
Q

Where is maltose found biologically / used

A

It is found in germinating seeds and used for brewing

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13
Q

What bond is present in maltose (between the monosaccharides)

A

An alpha 1-4 glycosidic bond

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14
Q

What is sucrose

A

A disaccharide made of alpha glucose and fructose

An alpha 1-2 glycosidic bond is formed

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15
Q

What the biological role of sucrose and what do we use it for

A

It is used to transport energy in plants
We use it in cooking

It is stored in sugar cane

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16
Q

What bond is formed between the monosaccharides in sucrose

A

An alpha 1-2 glycosidic bond

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17
Q

What is lactose

A

A disaccharide formed by alpha glucose and galactose

There is a beta 1-4 glycosidic bond between the monosaccharides

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18
Q

What is the biological role of lactose and what do we use it for

A

It is found in mammalian milk to supply energy

We use it in food (e.g cheese)

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19
Q

What bond is formed between the monosaccharides in lactose

A

A beta 1-4 glycosidic bond

20
Q

How is it determined whether a glycosidic bond is alpha or beta

A

If the OH groups on C1 and C4 are both below or both above the carbon, and alpha bond will form

If one is above and one is below a beta bond will form

21
Q

How are Disaccharides broken down

A

In hydrolysis reactions ( 1 H2O is added)

22
Q

When do humans break down disaccharides

A

They are broken down during digestion
(In reactions catalysed by enzymes)

23
Q

What is glycogen

A

A highly branched, not coiled polysaccharide found in animals and fungi

It is made by alpha glucose monosaccharides forming 1-4 glycosidic bonds
(And 1-6 glycosidic bonds every 10 units)

24
Q

Why is glycogen highly branched

A

Having many branches means that there are many terminal ends for enzymes to join to

This means glycogen can be quickly broken down (which is needed to maintain a high metabolic rate)

25
Q

What is glycogen used for

A

Glycogen is used to store energy
As it is compact it can store a lot of energy in a small space

26
Q

What is glycogen used for

A

Glycogen is used to store energy
As it is compact it can store a lot of energy in a small space

27
Q

Where is the energy in polysaccharides (such as glycogen) stored / located

A

In the glycosidic bonds between monosaccharides

28
Q

What is starch

A

A polysaccharide found in plants that is used to store energy

It is made of two types - amylose and amylopectin

29
Q

What is amylose

A

A type of starch

It is unbranched, linear and coiled in a helix
It contains alpha 1-4 glycosidic bonds between alpha glucose molecules

30
Q

What is amylopectin

A

A type of starch

It is branched (every 20 minutes) and not coiled
There are alpha 1-4 and 1-6 glycosidic bonds between alpha glucose

31
Q

Why does amylopectin have less branches than glycogen

A

As plants have a lower metabolic rate

32
Q

Why are starch and glycogen suitable storage molecules

A

Glycogen + amylopectin are branched, so they can be hydrolysed easily (quick energy release)

They are compact → store a lot of energy.
They are large → do not cross surface membranes

They are insoluble → They do not dissolve in water, so they have no osmotic effect

33
Q

What is cellulose

A

It is a linear and unbranched polysaccharide used structurally in plants

It is made from 1-4 glycosidic bonds between beta glucose

Several cellulose fibers form hydrogen bonds between each other

34
Q

What is the purpose of cellulose

A

Cellulose is used structurally, and it can be found most commonly in plant cell walls.

35
Q

Where are triglycerides found

A

in fats and oils

36
Q

What is a triglyceride made of

A

Glycerol and 3 fatty acids

There is an ester bond between the glycerol and each fatty acid

37
Q

What reaction forms triglycerides

A

Condensation reactions - 3 water is produced

38
Q

How are triglycerides broken down

A

In hydrolysis ( 3 water is added)

39
Q

what are saturated fats

A

Fats made of triglycerides that contain (saturated) fatty acids with a c-c bonds

40
Q

Why are saturated fats solid at room temperature

A

The fatty acids are linear and unbranched so the triglycerides can pack closer together
This makes the intermolecular forces between the triglycerides harder to break so they are solid at room temperature

41
Q

What are unsaturated fats

A

Fats which contain unsaturated fatty acids with a C=C double bond

This means that they have bends (or kinks) in their Carbon chain

42
Q

Why are unsaturated fatty acids liquid at room temperature

A

Due to the kinks in the carbon chains the trigkycerides do not pack closely together.

This means the intermolecular forces between them are weaker, and require less energy to break

43
Q

Why does the hydrolysis of triglycerides decrease the pH of a solution

A

As fatty acids are acidic

Hydrolysis of triglycerides releases fatty acids into the solution, causing the pH to decreases

44
Q

How do beta glucose molecules form alpha 1-4 glycosidic bonds

A

The molecules inverts after every bond is formed. This ensures the OH groups are always in the same position

45
Q

Whats the minimum number of monosaccharides needed to make a polysaccharide

A

10

(A Level) Biology (8 decks)

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