Inorganic ions

Question 1

what is an ion?

Answer 1

an atom that has an electrical charge

Question 2

what is an ion with a positive charge known as?

Answer 2

a cation

Question 3

what is an ion with a negative charge known as?

Answer 3

anion

Question 4

what is an inorganic ion?

Answer 4

an ion which does not contain carbon

Question 5

where do inorganic ions play an important role?

Answer 5

in many essential cellular processes

Question 6

where do inorganic ions occur?

Answer 6

They occur in solution in the cytoplasm and body fluids of organisms
- some occur in high concentrations others in very low concentrations

Question 7

where can the concentration of certain ions fluctuating be used?

Answer 7

cell signalling

neuronal transmission

Question 8

inorganic ions in the body

Answer 8

•Hydrogen ions H+
•Iron ions Fe 2+ / Fe 3+
•Sodium ion Na +
•Phosphate ions PO4 3-
•Calcium ions Ca 2+

Question 9

what are hydrogen ions?

Answer 9

protons

Question 10

what does the concentration of H+ in a solution determine?

Answer 10

the pH

Question 11

what is the relationship between the pH value and the hydrogen ion concentration?

Answer 11

inverse relationship
• the more H+ ions present
the lower the pH
( more acidic solution )

• the fewer H+ ions presents
the higher the pH
( more alkaline solution )

Question 12

what is the concentration of H+ very important for?

Answer 12

enzyme - controlled reactions
which are really affected by pH

fluids in the body normally have pH value of approximately 7.4

the maintenance of this normal pH is essential for many of the metabolic processes that take place within the cells

Question 13

How can changes in pH affect enzymes?

Answer 13

can enzyme affect enzyme structure

e.g. abnormal levels of hydrogen ions can interact with the side-chains of amino acids and change the secondary and tertiary structures of the proteins that make up enzymes

— causes dénaturation

Question 14

what are the two versions of iron ions- oxidation states?

Answer 14

• iron (II) ions,
ferrous ions
Fe 2+

• iron (III) ions,
ferric ions
Fe 3+

Question 15

why are iron ions essential?

Answer 15

they can bind oxygen

transfer of electrons-
during respiration + photosynthesis

Question 16

where do iron ions bind oxygen?

Answer 16

Haemoglobin- is the large protein in red blood cells
responsible for transporting oxygen around the body

haemoglobin is made up of 4 polypeptide chains for that each contain one Fe 2+

the Fe 2+ is a key component in haemoglobin as it binds to oxygen

myoglobinin muscles functions in a similar way
- it is an oxygen binding protein
made up of one polypeptide chain
-containing one Fe 2+

Question 17

How are iron ions involved in the transfer of electrons?

Answer 17

-during respiration and photosynthesis
- key to biological generation of energy

iron ions are an essential component of cytochromes
( that are themselves a component of electron transport chains)
cytochrome c contains an iron ion that is essential to its function during the electron transport

during electron transport process
this iron ion switches between the Fe3+ and Fe2* oxidation states,
which allows for electrons to be accepted and donated

Question 18

what are sodium ions required for the transport of?

Answer 18

glucose and amino acids across cell surface membranes

transmission of nerve impulses

Question 19

what does the process of co-transport consist of?

Answer 19

glucose and amino acids molecules can only enter cells through carrier proteins alongside Na +

1- Na+ is actively transported out of the epithelial cells that line the villi
the Na+ concentration inside the epithelial cells is now lower than the Na+ concentration in the lumen of the small intestine

2- Na+ now re enters the cells
(moving down the concentration gradient) through co transport on the surface membrane of the epithelial cells,
allowing glucose and amino acids to enter at the same time

Question 20

what do phosphate ions do?

Answer 20

PO4 3- attaches to other molecules to form phosphate groups
essential component in DNA, RNA, ATP

In DNA+ RNA phosphate groups allow individual nucleotides to join up
to form polynucleotides

In ATP the bonds between phosphate groups store energy
- these phosphate groups can be easily attached or detached
-when the bonds between phosphate groups are broken, they release a large amount of energy, which can be used for cellular processes

found in phospholipids- key components of the phospholipid bilayer of cell membranes

Question 21

How are calcium ions essential in the movement of organisms?

Answer 21

in synapses, calcium ions regulate the transmission of impulses from neurone to neurone

Question 22

how do calcium ions stimulate muscle contraction?

Answer 22

-when an impulse reaches a muscle fibre , Ca 2+ is released from the sarcoplasmic reticulum

• this Ca 2+ binds to troponin C, removing the tropomyosin from myosin-binding sites on actin

-this allows actin- myosin cross bridges to form when the muscle fibre contracts

Question 23

what can Ca 2+ do to protein channels?

Answer 23

it can help regulate protein channels
which affects the permeability of cell membranes

Question 24

what are many enzymes activated by?

Answer 24

Ca 2+
making these ions key regulators in many biological reactions

Question 25

what enables blood clots to form?

Answer 25

Ca 2+ a clotting factor