ion and cell function

Ion

An atom (or sometimes a group of atoms) that has an electrical charge.

Cation

An ion that has a positive charge.

Anion

An ion that has a negative charge.

Inorganic Ion

An ion that does not contain carbon.

Concentration of Ions

The amount of certain ions that can fluctuate and can be used in cell signalling and neuronal transmission.

Hydrogen Ions (H+)

Protons that determine the pH of a solution.

pH

The measure of acidity or alkalinity of a solution

Inverse Relationship of pH and H+

The more H+ ions present

the fewer H+ ions present

the higher the pH (the more alkaline the solution).

Normal Body pH

The fluids in the body normally have a pH value of approximately 7.4.

Iron Ions

There are two versions known as oxidation states: Iron (II) ions (Fe2+) and Iron (III) ions (Fe3+).

Role of Iron Ions

Essential as they can bind oxygen.

Haemoglobin

The large protein in red blood cells responsible for transporting oxygen around the body

Sodium Ions (Na+)

Required for the transport of glucose and amino acids across cell-surface membranes.

Co-Transport

The process where glucose and amino acid molecules enter cells alongside Na+ through carrier proteins.

Transmission of Nerve Impulses

A function that requires sodium ions (Na+).

Phosphate Ions (PO43-)

Attach to other molecules to form phosphate groups

Phosphate Groups in DNA/RNA

Allow individual nucleotides to bond to form polynucleotides.

Phosphate Groups in ATP

Store energy in the bonds between phosphate groups.

Energy Release from Phosphate Bonds

When the bonds between phosphate groups are broken

Phospholipids

Key components of the phospholipid bilayer of cell membranes.

Examiner Tips

Know the properties and roles of hydrogen ions (H+)

Nucleus

contains genetic material (DNA) and controls cell's activities

Ribosomes

use genes for protein synthesis by joining amino acids

Endoplasmic reticulum

sheets of membranes that manufacture

Rough (RER)

has ribosomes on surface- to synthesis proteins

Smooth (SER)

synthesis of lipids and carbohydrates

Golgi apparatus

modifies the proteins and lipids that are produced in the ER. IT ALSO LABELS THEM SO THEY CAN BE SORTED AND SENT TO CORRECT LOCATIONS

Mitochondria

site of respiration to release energy. Responsible for the production of ATP (energy carrier molecule). Use for active transport

Lysosomes

a specific example of a Golgi vesicle: Break down dead cells

Vacuoles

found in plants and usually contains cell sap. This occupies 80-90% of the plant cell and is mainly made up of water