Terms P - R

Question 1

Palisade Cells

Answer 1

long narrow cells packed with Chloroplasts that are found in the upper region of a leaf and which carry out photosynthesis

Question 2

Passive immunity

Answer 2

Resistance to a disease that is acquired from the introduction of ANTIBODIES from another individual rather than an individuals own immune system eg across placenta or via mothers milk - usually short lived

Question 3

Pathogen

Answer 3

Any microorganism that causes disease.

Question 4

Pentose sugar

Answer 4

A sugar that possesses five carbon atoms. Two examples ribose and deoxyribose

Question 5

Peptide Bond

Answer 5

The chemical bond formed between two amino acids during CONDENSATION

Question 6

Phagocytosis

Answer 6

Mechanism by which cells engulf particles to form a vesicle or a vacuole

Question 7

Phospholipid

Answer 7

Triglyceride in which one of the three fatty acid molecules is replaced by a phosphate molecule. Phospholipids are important in structure and functioning of plasma membranes

Question 8

Photomicrograph

Answer 8

Photograph of an image produced by a microscope

Question 9

Plasmid

Answer 9

A small circular piece of DNA found in bacterial cells

Question 10

Plasmodesmata

Answer 10

Fine strands of cytoplasm that extend through pores in adjacent cell walls and connect the cytoplasm of one cell with another

Question 11

Plasmolysis

Answer 11

The shrinkage of cytoplasm away from the cell wall that occurs as a plant cell loses water by OSMOSIS

Question 12

Polymer

Answer 12

Large molecule made up of repeating smaller molecules (monomers)

Question 13

Polymerases

Answer 13

Group of enzymes that catalyse the formation of long chain molecules (polymers) from similar basic units

Question 14

Polyunsaturated fatty acid (PUFA)

Answer 14

Fatty acid that losses carbon chains with many double bonds

Question 15

Primary structure of a protein

Answer 15

The sequence of amino acids that makes up the polypeptides of a protein

Question 16

Prokaryotic cell

Answer 16

A dell of an organism belonging to the kingdom prokaryotae that is characterised by lacking a nucleus and membrane-bound organelles eg bacteria

Question 17

Protoplast

Answer 17

The living portion of a plant cell this is the nucleus and cytoplasm along with the organelles it contains

Question 18

Quaternary structure of protein

Answer 18

A number of polypeptide chains linked together - sometimes associated with non-protein groups to form a protein

Question 19

Reduction

Answer 19

Chemical process involving the gain of electrons