Exam 1

Question 1

The four elements that make up about 96% of body matter are

Answer 1

carbon, oxygen, hydrogen, nitrogen

Question 2

What is the difference between a solution and a suspension?

Answer 2

Solution: very tiny particles that do not settle or scatter light.
Suspension: large particles that settle and may scatter light

Question 3

Salts are always

Answer 3

Ionic compounds

Question 4

The acidity of a solution

Answer 4

is positively related to pH

Question 5

Colloid solution

Answer 5

Solute particals are larger than in a solution and scatter light + do not settle out. ie: Jelly

Question 6

solute solution

Answer 6

Solute particles are very tiny. They do not settle or scatter light. ie: Mineral Water

Question 7

Suspension solution

Answer 7

Solute particles are very large, they settle and scatter light. ie: blood

Question 8

What is a molecule?

Answer 8

two or more of the same element

Question 9

What is a compound?

Answer 9

two or more different elements
They are also chemically pure and have different properties to their individual atoms.

Question 10

Chemically Inert vs Reactive

Answer 10

Chemically inert: valence shell full
Chemically reactive: valence shell incomplete

Question 11

Three key features of an acid

Answer 11

Proton donor (hydrogen), release hydrogen into a solution and has a higher level of hydrogen

Question 12

Three key features of a base

Answer 12

Proton acceptor, take up hydrogen from a solution, and has a lower level of hydrogen

Question 13

Dehydration Synthesis

Answer 13

The process of joining two monosaccharides together with the removal of water to form a disaccharide

Question 14

What are the three points of cell theory?

Answer 14

1. The Cell is the smallest unit of life
2. All organisms are made of one or more cells
3. Cells only arise from other cells via mitosis / meiosis

Question 15

What are the three main parts of the human cells?

Answer 15

1. Plasma Membrane - outer boundary of the cell
2. Cytoplasm - intracellular fluid packed with organelles
3. Nucleus - control centre

Question 16

What is the plasma membrane?

Answer 16

It is a phospholipid bilayer with embedded proteins arranged as a fluid mosaic.

Question 17

What basic structure do all cell membranes share?

Answer 17

Lipids
a) phospholipids - have hydrophobic tails that prevent water-soluble substances from crossing therefore becoming a boundary
b) Cholesterol - Stiffens the membrane (typical 4 ring steroid)

Proteins
Determine what function the membrane can perform. Different shaped proteins have different functions.

Carbohydrates
Allow cells to know “who is who” - recognition - these are found on the outer surface of the membrane-like sugar on a breaky cereal.
Really important within the immune system - and ID anyone who is foreign.

Question 18

6 functions of the Protein Membrane:

Answer 18

1. Transport - hydrophilic channel for a protein (integral)
2. Reception for signal transactions
3. Enzymes - cause reactions to occur
4. Cell top cell recognition - ID tags - the immune system can identify if anything is foreign
5. Cell shape
6. Cell-to-cell joining - for transport or nutrients

Question 19

Functions of the Plasma membrane?

Answer 19

Physical barrier: encloses the cell and seperates the cytoplasm from the extracellular fluid

Selective permeability: determines which substance enter and exit the cell

Communication: plasma membrane proteins interact with specific chemical messengers and relay messages to the cell interior.

Cell recognition: cell surface carbs all cells to know who is who.

Question 20

What makes up Extracellular Fluids (ECF)?

Answer 20

a) Interstitial fluid
b) blood plasma
c) cerebrospinal fluid
– Dissolves and transports substances in the body

Question 21

Explain the phospholipid bilayer

Answer 21

Double layer of phospholipids with embedded proteins which is commonly referred to as a ‘fluid mosaic model’
Parts:
▪ Membrane lipids = lipid bilayer (phospholipids + cholesterol)
– Phospholipids – hydrophilic head + hydrophobic tails
– Cholesterol ~20%
▪ Membrane proteins
– Allow communication with the environment from inside to outside.
– Responsible for specialised functions - some move and some are more fluid

Question 22

Plasma Membrane - Cell Junctions

Answer 22

Tight - zipper - prevent molecules from passing between the cells ie. the stomach
Desmosomes - velcro - anchoring junctions - form the cells into rows / sheets
Gap - communicating junctions - lock and key - allows ions and molecules to pass between the cells - ie. heart and embryonic cells.

Question 23

Passive v Active

Answer 23

Passive - no energy needed - from high to low substance movement
Diffusion = the movement of molecules or ions from an area where they are in higher concentration to an area where they are in low concentration. - CONCENTRATION GRADIENT

Active - requires energy (ATP) - can move from low to high

Question 24

The speed of diffusion is influenced by the following:

Answer 24

Concentration
Molecular size
Temp

Question 25

What is Tonicity

Answer 25

ability of a solution to change the shape of cells by altering the cells internal water volume.

Question 26

Joints / Articulation

Answer 26

Site where two or more bones meet

Question 27

An elevated ridge of the cortex is called a

Answer 27

Gyrus