2: Molecules to Metabolism Flashcards Preview

IB Biology SL > 2: Molecules to Metabolism > Flashcards

Flashcards in 2: Molecules to Metabolism Deck (28):
1

Are living and non-living things made out of different materials? What is the accepted belief now?

- no
- living organisms are governed by the same chemical and physical forces as non-living organisms

2

What was the 'theory of vitalism'? How was it falsified?

- that l.o were composed of organic chemicals
- that could only be produced in l.o because a 'vital force' was needed

-synthesizing urea artificially (among other discoveries)

3

What does the science of molecular biology aim to explain?

living processes in terms of the chemical substances involved

4

A 'vital force' does not explain the difference between living organisms and non-living matter. What idea better demonstrates the differences between living and non-living?

natural selection

5

What was discovered about human urine in the 18th Century?

human urine contained urea

6

What sort of compound is urea?

an organic compound

7

Draw the structure of urea. (p17)

-

8

Why was it believed that urea could only be made in living organisms?

because urea is an organic compound so it was believed that a vital force was needed (theory of vitalism)

9

Who and when synthesized urea artificially? How did they do it?

Why was this significant?

- German chemist Friedrich Wohler
- 1828
- silver isocyanate and ammonium chloride

- was the first time an organic compound was synthesized artificially which helped falsify the theory of vitalism. Scientific theories are rarely abandoned until several pieces of evidence show them to be false.

10

What is an atom?

a single particle of an element, consisting of a positively charged nucleus surrounded by a cloud of negatively charged electrons

11

What is a molecule?

a group of two or more atoms held together by covalent bonds (single, double, or even triple bonds)

12

Draw the chemical structure of ethanol.

-

13

Draw the chemical structure of carbon dioxide.

-

14

Draw the chemical structure of nitrogen. What sort of molecule of this?

-
- nitrogen is an element

15

Draw the chemical structure of hydrogen cyanide. What sort of molecule of this?

-
- compound because 2+ separate elements bonded together

16

What are the molecules used by living organisms based on?

carbon

17

How many and of what sort of bonds can one carbon atom form? What is the significance of this?

- 4 covalent bonds
- allowing great diversity of compounds to exist

18

What are the chemical symbols for nitrogen, hydrogen, carbon, and oxygen? How many covalent bonds can each element form?

1. N, H, C, O
bonds = 3, 1, 4, 2

19

Covalent bonds are relatively strong. What can be said about molecules that are formed by covalent bonds? Give an example of a much weaker bond.

- molecules have stable structures
- intermolecular forces

20

State the main types of molecule used by living organisms?

carbohydrates, lipids, proteins, and nucleic acids

21

Define 'metabolism'.

the web of all the enzyme-catalysed reactions in a cell or organism

22

What do most metabolic pathways consist of?

chains of reactions but there are also some cycles of reactions

23

Define 'anabolism'.

the synthesis of complex molecules from simpler molecules

24

What are macromolecules? What are macromolecules made up of?

- very large molecules produced by living organisms
- made up of smaller sub-unit structures called monomers

25

What type of reactions are anabolic reactions? Why?

- condensation reactions
- because water is produced

26

Define 'catabolism'.

the breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers

27

What happens in hydrolysis reactions?

molecules are split

28

What sort of reactions are catabolic reactions? Why?

- hydrolysis reactions
- because water is used to split the molecules

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