2. Carbohydrates And Monosaccharides Flashcards Preview

AQA A LEVEL BIOLOGY 🌿 > 2. Carbohydrates And Monosaccharides > Flashcards

Flashcards in 2. Carbohydrates And Monosaccharides Deck (23)
Loading flashcards...
1
Q

Carbon containing molecules are also known as __________

A

Organic molecules

2
Q

What is the basic monomer unit in carbohydrates?

A

A sugar (saccharide)

3
Q

A pair of monosaccharides can be combined to form a __________

A

Disaccharide

4
Q

Monosaccharides can be combined in much larger numbers to form __________

A

Polysaccharides

5
Q

Describe a monosaccharide

A

Sweet tasting
Soluble
General formula (CH2O)n
(n can be any number from 3 to 7)

6
Q

Name three examples of monosaccharides

A

Glucose
Galactose
Fructose

7
Q

Glucose is a __________ sugar

A

Hexose (6 carbon)

8
Q

General formula of glucose?

A

C6H12O6

9
Q

Name the two isomers of glucose

A

Alpha glucose

Beta glucose

10
Q

Difference between alpha and beta glucose?

A

The two H’s are at the top and the OH’s are at the bottom in alpha glucose but in beta glucose they’re on opposite sides

11
Q

All monosaccharides and some disaccharides are..?

A

Reducing sugars

12
Q

Describe reduction

A

A chemical reaction involving the gain of electrons or hydrogen

13
Q

What is a reducing sugar?

A

A sugar that can donate electrons to (or reduce) another chemical

14
Q

Name of test for a reducing sugar?

A

Benedict’s test

15
Q

Benedict’s reagent is..

A
An alkaline solution 
Of copper(II) sulfate
16
Q

What happens when a reducing sugar is heated with Benedict’s Reagent?

A

An insoluble red precipitate of copper(I) oxide is formed

17
Q

Benedict’s Test: ?

A

1) Add food sample to a test tube. Grind up sample in water is sample is not already in liquid form
2) Add an equal volume of Benedict’s reagent
3) Heat the mixture in a gently boiling water bath for five minutes

18
Q

Colour change in Benedict’s test if reducing sugar is present..?

A

Blue to orange-brown

19
Q

Benedict’s test is a __________ test

A

Semi quantitative

20
Q

Results of Benedict’s test according to the concentration of reducing sugar present

A
Blue = none
Green = very low
Yellow = low
Orange = medium
Red = high
21
Q

Large molecules often contain carbon. Explain why this is.

A

Carbon atoms readily link to one another to form a chain

22
Q

State the general name for a molecule that is made up of many similar repeating units

A

Polymer

23
Q

Explain why Benedict’s reagent turns red when heated with a reducing sugar

A

Sugar donates electrons that reduce blue copper(II) sulfate to copper(I) oxide