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Flashcards in CH 2 Molecules of Life Deck (58):
1

What is an atom?

The basic unit of matter

2

What is an isotope?

Atoms of the same element that have a different number of neutrons

3

Define an ion and provide an example.

An electrically charge atom. H+ is positively charged because it has lost an electron

4

Define orbital.

A region in space likely to host an electron

5

What is an atomic shell?

An energy level within an orbital.Electron will choose to occupy the shell closest to the nucleus first

6

What is the periodic table?

Elements are arranged by increasing number of protons, the atomic number. Elements in the same column share similar chemical properties.

7

What is a molecule?

A combination of atoms

8

Define a chemical bond?

A form of attraction between atoms that hold them together

9

What are valence electrons?

Electrons located at the highest energy level. Responsible for chemical bonding

10

What is a molecular orbital?

A merged orbital between two electrons

11

Define covalent bond

It is the sharing of electrons to form a molecular orbital

12

What is a polar covalent bond?

The unequal sharing of electrons. Occurs due to differences in the electro negativity of atoms

13

Define electro negativity?

Increases along the periodic tableAs the number of protons increases electrons are held more tightly to the nucleus therefore less likely to transfer an electron

14

What is a hydrogen bond?

Occurs when a H atom is covalently bonded to an electronegative atom (oxygen or nitrogen) interacts with an electronegative atom of another moleculeWeaker than covalent bonds

15

What are ionic bonds?

Bond between two ionsNa+ and Cl- form NaCl

16

What's a polar molecule?

A molecule that has a + and a - regions

17

Define hydrophilic?

Water loving

18

Define hydrophobic?

Water fearing

19

What is the hydrophobic effect?

Polar molecules exclude non polar ones.Example cell membrane

20

When does a neutral PH occur?When does a acidic PH occur?When does a basic PH occur?

Neutral PH occurs when H+ = OH-Acidic PH occurs when H+ is greater than OH-Basic PH occurs when H+ is less than OH-

21

Why is ice less dense than water?

When water freezes the molecules bond with four other molecules into a crystal lattice structure. Making ice less dense

22

Define cohesive force?

Tendency to stick together

23

What is surface tension?

Contrastive tendency of the surface of a liquid to resist an external force

24

What is an element?

A pure substance that cannot be broken down further by chemistry

25

What is an organic molecule?

A molecule that contains carbonForms tetrahedronsAbility to rotate around a single bond. Cannot rotate around a double or triple bond

26

Define isomer?Give an example

Molecules that have the same chemical formulae but have different structures.Lucine and isoleucine

27

What do proteins do?

Provide structural support and act as catalysts during chemical reactions

28

What is the role of nuclei acids?

Encode and transmit genetic information

29

What is the role of carbohydrates?

Provide energyMakes up cell wall in plants, bacteria and algae

30

What is the purpose of lipids?

Store energyMake cell membranes Act as a signalling molecule

31

What is a polymer?What are the four main examples?

Complex molecules made up of repeated simpler units connected by covalent bondsAmino acids make up proteins Sugars make up carbohydratesFatty acids make up lipidsNucleotides make up nucleic acid

32

What is an enzyme?

Protein based catalysts that accelerates the rate of chemical reactions

33

Describe a peptide bond

Links amino acids by the C atom of the carboxyl group to the N atom of the amino group

34

What is DNA?

The genetic material in all organisms

35

What's is RNA?

Key player in protein synthesis and regulation of gene expression

36

What is a phosphodiester bond?

Joins adjacent pair of nucleotides using a phosphate group

37

Explain a double helix

Two strands of nucleotides twisted around each other

38

Define saccharides

Simplest form of sugars Form in linear or cyclic molecules

39

What is the composition of sugars and what is the ratio?

Composed of C H O in a 1:2:1 ratio

40

What is a monosaccharide, disaccharide, polysaccharide?

One simple sugar, two simple sugars linked by covalent bonds, combination of simple sugars

41

What is a complex carbohydrates?

Long branched chains of monosaccharides

42

Define aldoses

Monosaccharides with an attached aldehyde group

43

Define ketoses

Monosaccharides with an attached ketone group

44

What are glycosidic bonds?

Covalent bonds that attach monosaccharides

45

Define triacylglycerol

Lipid used for energy storageMade up of three fatty acids joined to glycerol

46

Define saturated fat

Fatty acids that do not contain a double bond

47

Define unsaturated fat

Fatty acids that contain a C-C double bond

48

Why are the kinks found in a fatty acid chain important?

Reduce tightness and therefore lower the melting point

49

Describe van der waal forces

Temporarily polarized molecules weakly bonded to one another due to the attraction of opposite forces

50

Define steroids

Second type of lipids Example cholesterol

51

Define phospholipids

Third type of fatty acids major component of cell membranes

52

Describe the Stanley miller experiment

Water vapour, ammonia, methane and hydrogen gas and collected. A spark is introduced and the formation of 20 amino acids is the result

53

Know difference between RNA and DNA chemical structure

Ok

54

Be able to identify nucleic acids

Ok

55

Identify a phosphodiester bond

Ok

56

Know the three types of carbohydrate molecules

Ok

57

How are amino acids joined in a protein?

By a peptide bond

58

Recognize a fatty acid molecule

Ok