1.0 Biological Molecules Flashcards
1
Q
All matter is made up of what?
A
Atoms
2
Q
What are the 3 particles an atom is made up of?
A
- Protons, which have a +ve charge
- Neurtons, which have no charge
- Electrons, which have a negative charge
3
Q
What is the structure of an Atom
A
- A central nucleus contains the protons and neutrons
- The electrons circle the nucleus in orbitals or shells
4
Q
If the overall charge of an atom is neutral, what is the ratio of protons and electrons
A
- The number of protons and electrons are the same
5
Q
How many protons do atoms of the same element contain e.g. Carbon
Same
More
Less
A
- The same
6
Q
How many protons do carbon atoms have?
A
- 6
7
Q
How many protons do oxygen atoms have?
A
8
8
Q
What is the atominc number
A
The number of protons contained in the nucleus
9
Q
What is the mass number of an element
A
The number of protons plus the number of neutrons contained in the nucleus
10
Q
What is a molecule?
A
- A molecule consists of 2 or more atoms joined together chemically:
- The molecules in an atom can be the same
- Eg Oxygen has 2 atoms of oxygen (O2)
- Or the atoms can be different
- Eg Carbon Dioxide has one atom of carbon and 2 atoms of Oxygen (CO2)
11
Q
What is the name given to a molecule which is composed of different atoms?
A
- A Compound
- e.g. CO2
12
Q
What is an Ion?
A
A charged particle
13
Q
How is an ion formed?
A
When an atom or groups of atoms lose or gain electrons
14
Q
What type of charge does an electron have?
A
- Negative
15
Q
If an atom gains an electron what happens?
A
- It becomes an Ion with a negative charge
16
Q
What is the name given to Ions with a negative charge
A
- Anions
- AN IONS
17
Q
What happens when atoms lose electrons
A
- Ions have a positive charge
18
Q
What do you call Ions with a positive charge?
A
Cations
CAT IONS
19
Q
A sodium atom which loses an electron is written how?
A
- NA+
20
Q
A chlorine atom which gains an electron
A
- CL-
21
Q
How do you write a nitrate ion
A
N03-
22
Q
How do you write a phosphate ion
A
PO43-
23
Q
What is an isotope?
A
An atom composed of the same elements with a different mass number
24
Q
What do some biologists use isotopes for?
A
- They are used as tracers because they are radioactive
25
How do you write radioactive isotope carbon 14
* 14C
26
How can 14C be used?
* If it is fed to plants you can look at the formation of compunds made in photosynthesis by tracing what happens to the 14C
27
Hydrogen - What is the...
Atomic number
Mass number
* Atomic number - 1
* Mass number - 1
28
What is the structure of a Hydrogen atom?
* 1 proton
* 1 electron
* No neutrons
29
How do you write a hydrogen Ion which has lost an electron?
* H+
30
What is pH
* The measure of the concentraton of hydrogen ions present
31
What if a pH is high?
* High pH
* High concentration of Hydrogen Ions
* More acidic the solution
32
What is the range of a pH scale
1 to 14
33
On the pH scale a value of 1 means what
Highly acidic
34
On the pH scale a value of 7 means what
Neutral
35
On the pH scale a rating of 14 means what?
Stongly alkaline
36
What type of scale is the pH scale, logarithmic or not logarithmic?
Logarithmic
37
How much stronger is a pH of 1 vs a pH of 2
10 times more acidic
38
How much stronger is a pH of 2 vs a pH of 3
10 times more acidic
39
How much stronger is a pH of 1 vs a pH of 3
20 times more acidic
40
How much more acidic is a pH of 1 vs a pH of 7
70 times more acidic
41
What happens when an acid is placed in solution
It breaks up into ions (dissociates)
42
What happens when hydrochloric acid is placed in solution?
HCL acid → H+ → CL-
Hydrochloric acid splits
43
What happens when an Acid loses a hydrogen ion?
It leaves a base...
44
What is a base
Any chemical which can combine with hydrogen ions
45
What happens when the base NCO3- accepts a hydrogen ion?
* NCO3- + H+ → HNO3
Base + Hydrogen Ion = Acid
46
What is a buffer?
A chemical which can act as both a base or an acid
47
What type of proteins keep the blood at a constant pH
Plasma proteins act as bases preventing the blood from becoming too acid or alkaline
48
What happens when a base and acid react together
They form salts.
49
What holds the atoms together inside a molecule
A chemical bond
50
electrons which circle a nucleus are found in what
Orbitals or Shells
51
How many electrons can the first orbital hold
2
52
How many electrons can the second and third orbitals hold
8
53
How many electrons can the subsequent orbitals/shells hold
An increasing number e.g. more than 8
54
What happens when there is a positive sodium ion and a negative chloride ion
Attract
Move appart
Nothing
They are attracted to each other
55
What is the name given when a negative and positive ion are drawn together
Ionic Bond
56
In which type of compound can ionic bonds be seen
Sodium chloride
The Sodium (Na) loses an electron to become Na+
The Chloride gains an electrion to become CL-
An ionic bond is formed between the two ions.
57
Whas is a covalent bond
A covalent bond occurs when one atom shares electrons with another atom.
e,g, Carbon has four electrons in its outer shell
It would become more stable if it gains 4 more electrons
Methane CH4 consists of carbon plus 4 hydrogen atoms
58
What is the structure of a water molecule
A water molecule has
* 2 hydrogen atoms
* 1 oxygen atom,
Each **oxygen** atom has: **6 electrons** in its outer shell and each **hydrogen** atom has **1 electron,**
NB: Each of the two hydrogen atoms share an electron with the oxygen (**Covalent Bond**)
59
When a molecule is said to be **polar** what does this mean?
A water molecule has **more protons** than electrons in its nucleus compared to each of the hydrogen atoms. These postively charged particles pull the shared electrons in the bond.
A water molecule contains H20, the oxygen end of the molecule has a slightly negative charge and the Hydrogen end of the molecule is slightly positive charge.
In such a case the molecule is described as polar.
60
What is a hydrogen bond
When two water molecules are in close contact, their opposing charges attract each other. This forms a hydrogen bond.
61
What is the most important property of water
It can stick together by forming **hydrogen bonds** with other water molecules
62
What type of charge does a water molecule have?
It is Neutral e.g. 10 protons and 10 electrons
63
How many protons and electrons does a water molecule have
10 protons
10 electrons
64
What type of molecules allow the formation of hydrogen bonds
Polar molecules
65
What is the name given to the sticking together of molecules
Cohesion
66
What happens when a chemical dissolves in water
It is free to move about and to react with other chemicals
67
What type of particles are attracted to water molecules
Water molecules have a slightly negative and positive charge and attract Ions and other polar molecules such as glucose.
e.g. The slightly negative charge of the Oxygen atom can attract the CATIONS Sodium and Potassium
68
What type of non polar molecules will not dissolve in water
Lipids
69
What is the name given to a substance which hates water
Hydrophobic
70
Why is water as a metabolite and transport medium important
* In many cellular reactions water is either lost (photosynthesis) or made (respiration)
* In animals, blood, tissue fluid and lymph transport many dissolved substances critical to health.
* In plants water plays an important role in the way Xylem and Phloem function
71
What sort of temperature range can most cells tolerate
Most cells can only function optimally within a **narrow temperature range** because the **enzymes** within them can only function optimally within this narrow range
72
What is the definition of specific heat capacity
Specific heat capacity is the amount of **heat energy required** to raise the **temperature** of a substance per unit of mass.
In SI units, specific heat capacity (symbol: c) is the amount of heat in **joules** required to raise 1 gram of a substance 1 **Kelvin**.
73
What type of substance has a high specific heat capacity
Water has a high heat capacity, which means that it needs a significant amount of heat energy to warm up and to lose a significant amount of heat energy to cool down
74
How do animal regulate temperature in a warm climate
Sweating involves the conversion of water to gas, which requires a significant amount of heat energy to escape from the body which cools it down.
75
Is water more dense as a liquid or ice
Water is more dense as liquid e.g. Ice floats on water, it does not sink.
76
At what temperature is water most dense
4 degree centigrade
77
What gives water its cohesive properties
Hydrogen bonds give water its cohesive properties
78
Is water easy to compress?
Water is virtually incompressable compared to air.
So an olympic swimmer tries to streamline their body through the water to improve their speed.
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