Topic 2 - Molecular Biology Flashcards Preview

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Flashcards in Topic 2 - Molecular Biology Deck (204)
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1

What is molecular biology?

Explaining biological processes in terms of the chemicals involved.

2

What are the four carbon compounds?

Carbohydrates, Lipids, Nucleic Acids, Proteins

3

What are the two types of enzyme-catalysed reactions?

Anabolism, Catabolism

4

Anabolism?

Forming macromolecules from monomers by condensation.

5

Catabolism?

Breaking complex macromolecules into simpler molecules by hydrolysis.

6

Example of biological compounds that can be synthesized outside of living things?

Urea

7

Falsification of vitalism?

Vitalism as a theory has since been disproven with the discovery that organic molecules can be artificially synthesised

8

Theory of vitalism?

doctrine that dictated that organic molecules could only be synthesised by living systems

9

How was the vitalism theory disapproved?

Frederick Woehler heated an inorganic salt (ammonium cyanate) and produced urea

10

Why was the theory of vitalism disapproved?

- Urea is a waste product of nitrogen metabolism and is eliminated by the kidneys in mammals
- The artificial synthesis of urea demonstrates that organic molecules are not fundamentally different to inorganic molecules

11

How many covalent bonds can carbon form?

4

12

Carbohydrates?

- Most abundant organic compound found in nature, composed primarily of C,H and O atoms in a common ratio – (CH2O)n
- Principally function as a source of energy (and as a short-term energy storage option)
- Also important as a recognition molecule (e.g. glycoproteins) and as a structural component (part of DNA / RNA)

13

Lipids?

- Non-polar, hydrophobic molecules which may come in a variety of forms (simple, complex or derived)
- Lipids serve as a major component of cell membranes (phospholipids and cholesterol)
- They may be utilised as a long-term energy storage molecule (fats and oils)
- Also may function as a signalling molecule (steroids)

14

Proteins?

- Make over 50% of the dry weight of cells; are composed of C, H, O and N atoms (some may include S)
- Major regulatory molecules involved in catalysis (all enzymes are proteins)
- May also function as structural molecules or play a role in cellular signalling (transduction pathways)

15

Nucleic Acids?

- Genetic material of all cells and determines the inherited features of an organism
- DNA functions as a master code for protein assembly, while RNA plays an active role in the manufacturing of proteins

16

3 Properties of carbon?

- Carbon has several allotropes, or different forms in which it can exist. These allotropes include graphite and diamond, which have very different properties.
- Despite carbon’s ability to make 4 bonds and its presence in many compounds, it is highly unreactive under normal conditions.
- Carbon exists in 3 main isotopes: 12C, 13C, 14C. 14C is radioactive and used in dating carbon-containing samples (radiometric dating).

17

Metabolism?

The sum of the chemical reactions that take place within each cell of a living organism and that provide energy for vital processes and for synthesizing new organic material.

18

Catabolism?

Breaking complex macromolecules into simpler molecules by hydrolysis.

19

Anabolism?

Forming macromolecules from monomers by condensation.

20

Why do hydrogen bonds occur in water?

Hydrogen atoms of one water molecule are attracted towards the oxygen atom of a neighboring water molecule

21

What are the 4 properties of water?

Adhesive
Thermal
Cohesive
Solvent

22

Solvent?

Water dissolves polar and ionic substances (forms competing polar associations to draw materials apart)

23

Cohesive?

Cohesion is the ability of like molecules to stick together

24

Thermal?

Water has the capacity to absorb significant amounts of heat before changing state (requires breaking of hydrogen bonds)

25

What does the di-polarity of a water molecule enable?

Enables it to form polar associations with other charged molecules (polar or ionic)

26

Why does water have the capacity to absorb significant amounts of heat before changing state?

Due to the extensive hydrogen bonding between water molecules – the H-bonds need to be broken before a change in state can occur and this requires the absorption of energy (heat)

27

Adhesive?

Adhesion is the ability of dissimilar molecules to stick together

28

What do the adhesive properties of water explain?

Capillary action

29

What do the cohesive properties of water explain?

Surface tension

30

How does dissolving occur in water?

The polar attraction of large quantities of water molecules can sufficiently weaken intramolecular forces (such as ionic bonds) and result in the dissociation of the atoms