Chapter 2 - Biological Molecules

What are organic compounds made of?

carbon, hydrogen, oxygen

What are the 3 different types of organic compounds?

carbohydrates, lipids , and proteins

What are carbohydrates made of?

carbon, hydrogen, oxygen

Monosaccharides

glucose, fructose, galactose

C₆H₁₂O₆

Chemical formula for glucose

Properties of monosaccharides

sweet, soluble in water, easily transportable

Glucose is found in:

Honey, blood

Fructose is found in:

Juicy fruits

Uses of monosaccharides

a product of photosynthesis in plants, used in respiration to release energy

Disaccharides

maltose, sucrose, lactose

Maltose is made of:

glucose + glucose

Sucrose is made of:

fructose + glucose

Lactose is made of:

glucose + galactose

How is starch broken down in digestion?

starch → maltose → glucose

Properties of disaccharides

sweeter and very soluble in water, easier to transport

Uses of disaccharides

In plants, carbohydrates are transported as sucrose, lactose is found in mammals' milk

What is maltose found in?

germinating seeds

What is sucrose found in?

flowering plants

What is lactose found in?

mammals' milk

Polysaccharides in plants are found as:

starch, cellulose

Polysaccharides in animals are found as:

glycogen, chitin

Properties of polysaccharides

insoluble in water, easier to store in cells, as molecular size increases, solubility decreases

What are polysaccharides found in?

plant cell walls, animal cells, exoskeleton of insects

Uses of polysaccharides

Store for carbohydrates (glycogen in animals and starch in plants)

What are lipids made of?

carbon, hydrogen, oxygen

What is the simple structure of Lipids?

1 glycerol combined with 3 fatty acids

How are lipids found in (a) plants (b) animals at room temperature?

(a) oils (b) fats

Properties of lipids

insoluble, forms emulsions with washing-up liquid

What are lipids used as?

Storage products

How are lipids used?

To provide energy, insulating layer under the skin

Why are they used as storage products?

Since they are insoluble and do not affect the osmotic pressure within the cells

Where else are lipids found?

In cell membranes

What are proteins made of?

carbon, hydrogen, oxygen, nitrogen, and a little sulfur/phosphorous

What are the three stages of protein?

amino acids - polypeptide - protein

How many amino acids are essential?

20 amino acids

In what is protein found?

albumen, haemoglobin, fibrinogen, carotene , cytoplasm, enzymes

The properties of proteins are:

Insoluble, denatured when heated

Proteins are needed for

growth and repair

Enzymes

Proteins that speed up chemical reactions

Protein is used for respiration...

when lipids or carbohydrates are not available

Why are proteins stored in animals and plants?

Because they are insoluble.

Organic compounds contain

carbon, hydrogen, oxygen

Inorganic compounds

don't contain carbon

Water is

inorganic

What is water?

Coolant, transport medium and habitat

Water dissolves substances, so it is called a ...

solvent

Water is a coolant because

it comes in forms of sweat and transpiration, and is used as a coolant

Water is

a reagent in many reactions, for example photosynthesis, breaking down starch to glucose, etc.

Turgidity

The plants are kept firm because the cells are full of water.