A - unit And Diversity (A1.1, A1.2)

Question 1

What are the physical and chemical properties of water that make it essential for life?

Answer 1

Water is polar
Water is less dense than solid then a liquid
Water has cohesive and adhesive properties

Question 2

What is adhesion?

Answer 2

Different molecules attract each other

Question 3

What is cohesion?

Answer 3

Like molecules attract each other

Question 4

Water is a solvent. what does it do?

Answer 4

Water helps molecular organisms transport molecules around a body and acts as the medium in which chemical reactions occur

Question 5

Water is a metabolite. What does it do?

Answer 5

Chemical reactions take place in cells. These reactions are called metabolism. Water is involved in photosynthesis and aerobic respiration.

Question 6

Water is temperature buffer what does this help with?

Answer 6

Water helps to buffer temperature changes in the cells because of its high specific heat capacity

Question 7

Water maintains, biological structures. Give some examples.

Answer 7

Water contributes to the formation of cell membranes
Water impacts the folding of proteins
Water surrounds DNA to support the double helix

Question 8

What do protons, neutrons and electrons carry? (charge.)

Answer 8

Protons carry a positive charge
Neutrons carry no net charge
Electrons have a negative charge

Question 9

What is an atom when the protons and electrons are equal?

Answer 9

Atoms are electrically neutral if they have an equal number of protons and electrons

Question 10

Why are electrons in an atom attracted to protons in the nucleus?

Answer 10

The nucleus has an electromagnetic force in which positive charge attracts negative charge

Question 11

What is atomic bonding?

Answer 11

Electrons can be transferred to another atom or is shared between atoms

Question 12

Name the four types of bonds

Answer 12

Nonpolar covalent bond
Polar covalent bond
Ionic bond
Hydrogen bond

Question 13

What is nonpolar and polar covalent bond

Answer 13

Nonpolar share electrons equally
Polar share electrons unequally

Question 14

What does ionic bonding

Answer 14

The attraction between positively charged ion and negatively charged ion

Question 15

What is a hydrogen bond?

Answer 15

An attraction between two polar molecules

Question 16

What is a polar molecule?

Answer 16

A molecule which one end of the molecule is slightly positive while the other end is slightly negative

Question 17

What is the water structure?

Answer 17

A water molecule consists of two hydrogen and one oxygen atom H2O

Question 18

What happens within a water molecule?

Answer 18

Electrons are shared through polar covalent bonding between the atoms

Question 19

Why is the water molecule polar?

Answer 19

Because oxygen atoms have more protons, which attracts the shared electrons more of the time, creating an unequal distribution of charge
+ hydrogen
- oxygen

Question 20

What do hydrogen bonds form between?

Answer 20

Water molecules

Question 21

What does the cohesion of water molecules allow?

Answer 21

Plants to move water under tension in xylem

Retains water on earth surface to serve as habitats

What contributes to physical properties of water important to living organisms

Question 22

What are xylem tissue’s?

Answer 22

They are long tubular vessels in vascular plants that form a continuous tube from the roots to the leaves

Question 23

What does lignin provide for a xylem?

Answer 23

Extra support for the plant as it grows up against gravity

Question 24

Water has a very high ———- ————?

Answer 24

Surface tension

Question 25

What causes water to have a very high surface tension?

Answer 25

Cohesive forces between molecules create surface tension

Question 26

What are polar and charged molecules called

Answer 26

Hydrophilic because they are attracted to water

Question 27

What is cellulose?

Answer 27

It’s a polymer made of glucose that is presented in plant cell walls

Question 28

What is the capillary action?

Answer 28

It’s the movement of water in through a narrow space with an opposition to external forces like gravity

Question 29

What does capillary action help with?

Answer 29

Bringing the water up into the roots with the help of adhesion and cohesion and water and dissolved ions, can move all the way up into the branches and leaves

Question 30

How do plants take in water?

Answer 30

Via osmosis

Question 31

Water is a solvent. What is a solvent, solute and solution

Answer 31

Solvent is the liquid in which a solute dissolves Solute is the substance that dissolves in a solvent Solution is a mixture of one or more solute dissolved in a solvent

Question 32

What happens when a solute dissolves in water?

Answer 32

They are molecules separate from each other and become surrounded by water molecules

Question 33

What is salvation?

Answer 33

It’s the interaction of a solvent with the dissolved solute

Question 34

Water forms, hydrogen bonds with a solute. What is this called?

Answer 34

Hydration shell around the solute

Question 35

Why will polar molecules dissolve in water?

Answer 35

They will dissolve because they are hydrophilic and can form hydrogen bonds with water

Question 36

Why will charged ions dissolve in water?

Answer 36

Because they are hydrophilic

Question 37

What happens if molecules are nonpolar with water?

Answer 37

They do not dissolve in water because they are hydrophobic

Question 38

What do water solvent properties allow it to be used as

Answer 38

As a medium for metabolism

Question 39

Why is water needed for cellular metabolism?

Answer 39

So it dissolves the reactants and enzymes so they can come together for reactions

Question 40

What are the types of enzyme reactions?

Answer 40

Catabolic and anabolic

Question 41

What do catabolic reactions do?

Answer 41

They break down large molecules into smaller molecules

Question 42

What do anabolic reactions do?

Answer 42

They build larger molecules for smaller molecules

Question 43

How are hydrophobic lipids transported around the body of an organism?

Answer 43

From a structure called Lipoprotein

Question 44

What are physical properties?

Answer 44

Observed and measured without changing chemical identity of sample For example, color length, volume

Question 45

What are chemical properties?

Answer 45

Observed and measured as a sample changes chemical identity For example, flammability, toxicity, acidity, reactivity

Question 46

What is buoyancy?

Answer 46

An upward force applied to an object that is immersed in fluid

Question 47

What is viscosity?

Answer 47

It’s a measure of fluids tendency to flow

Question 48

What is thermal conductivity?

Answer 48

A materials, ability to move heat across a temperature gradient

Question 49

What is specific heat capacity?

Answer 49

It’s the quantity of heat needed to raise the temperature of a chemical per unit mass