2.1 Molecules to metabolism

Question 1

What do we mean by organic?

Answer 1

Carbon containing

Question 2

What do living things contain a lot of? (4)

Answer 2

Hydrogen, oxygen, phosphorous, nitrogen

Question 3

Why is carbon special?

Answer 3

• It has tendency to form strong covalent bonds
• Valency of 4 so can bond with 4 other atoms - form long chains and complex molecules
• Can form single, double and triple bonds - extremely versatile
• Can form right and chain structures, framework atom

Question 4

What are all living things composed of? Which 4 main classes of carbon compounds? What do they have in common?

Answer 4

• Carbohydrate, lipids, proteins and nucleic acid
• Each have different structures but they all contain carbon, hydrogen and oxygen
• The differences in structures allows for different purposes

Question 5

What is carbohydrate characterized by?

Answer 5

their composition
* carbon, hydrogen and oxygen
* hydrogen and oxygen in the ratio of two hydrogen atoms to one oxygen

Question 6

What are lipids?

Answer 6

• a broad class of molecules that are insoluble in water, including steroids, waves, fatty acids and triglycerides
• are fats if they are solid at room temperature or oils if they are liquid at room temperature

Question 7

What are proteins composed of?

Answer 7

of one or more chains of amino acids.
* the amino acids contain the element carbon, hydrogen, oxygen and nitrogen
* but two of 20 amino acids also contain sulphur

Question 8

What are nucleic acids?

Answer 8

chains of subunites caled nucleotides
contain carbon, hydrogen, oxygen, nitrogen and phosphorous
there are two types: ribonucleic acid (RNA) and deoxyribonucleic acid (DNA)

Question 9

What is metabolism? What is metabolic rate?

Answer 9

The totality of chemical reactions that occur in an organism

The rate at which these chemical reactions take place.

Question 10

What is the difference between metabolism, anabolism and catabolism?

Answer 10

Anabolism builds complex molecules from simpler ones, while catabolism breaks large molecules into smaller ones

Metabolism is the totality of chemical reactions

Question 11

What are some processes of anabolism?

Answer 11

• Protein synthesis using ribosomes
• DNA synthesis during replication
• photosynthesis, including production of glucose from carbon dioxide and water
• synthesis of complex carbohydrates incuding starch, cellulose and glycogen

Question 12

What are some processes of catabolism?

Answer 12

• digestion of food in mouth, stomach and small intestine
• cell respiration in which glucose or lipids are oxidized to carbon dioxide and water
• digestion of complex carbon compounds in dead organic matter by decomposers

Question 13

Why do elements bond? How? What are the two types?

Answer 13

To achieve stability by gaining a full outer ring of electrons.

Ionic: transfer of electron, usually weaker bonds, metal to non-metal

Covalent: sharing of electrons, stronger bond, between non-metals

Question 14

What are hydrogen bonds? How strong are they? Where are they present in? How can they be broken?

Answer 14

Hydrogen bonds are the interactions that are formed between a slightly positive end of one molecule and a slightly negative end of an adjacent molecule.

• There a weak individually but strong together
• is present in DNA, water, cellulose, proteins
• can easily be broken by heat and pH changes

Question 15

How are dipoles created? What are the molecules with dipoles called?

Answer 15

• Dipoles are created when there’s a slight charge distribution and molecules.
• Molecules with dipoles are called polar

Question 16

What are monomers and polymers?

What is the monomer and polymer of these biological molecules: carbohydrates, proteins, nucleic acid?

Answer 16

Monomers are single small molecule which are joined together to form polymers.

Biological molecule -> monomer -> polymer

• Carbohydrate -> monosaccharide -> polysaccharide
• Proteins -> amino acids -> polypeptide
• Nucleic acids -> nucleotide -> nucleic acid (DNA, RNA)

Question 17

What is condensation and hydrolysis?

Answer 17

Condensation

1) Builds monomers into polymers
2) releases water
3) forms a new covalent bond

Hydrolysis

1) Breaks polymers into monomers
2) requires water
3) breaks covalent bonds

Question 18

Name three chemicals in living things which contain many carbon atoms

Answer 18

proteins, lipids, nucleic acids, and carbohydrates.

Question 19

What is a macromolecule?

Answer 19

A molecule containing a very large number of atoms, such as a protein, nucleic acid, or synthetic polymer.

Question 20

What are 3 examples of hydrolysis reactions in biological cells?

Answer 20

1) polypeptides + water -> dipeptide or amino acids
2) polysaccharides + water -> disaccharide or monosaccharide
3) glycerides + water -> fatty acids + glycerol

Question 21

What is urea?

Answer 21

a nitrogen-containing compounds with a relatively simple molecular structure

Question 22

When is urea produed?

Answer 22

when there is an excess of amino acids in the body, as a means of excreting the nitrogen from the amino acids

Question 23

Where is urea produced?

Answer 23

in the liver from a cycle of reactions, catalysed by enzymes

Question 24

Where is urea produced?

Answer 24

in the liver from a cycle of reactions, catalysed by enzymes

Question 25

What is the cycle of reactions occuring in liver cells that is used to synthesize urea?

Answer 25

ornithine cycle

Question 26

Draw the ornithine cycle

Answer 26

Question 27

What is the equation for producing urea in the body in words?

Answer 27

ammonia + carbon dioxide -> ammonium carbanate -> urea + water