(a) Explain the following terms: (i) disease (ii) symptoms of diseases. (b)(i) List two physical...

Explanation

(a)(i)Disease: A condition in which the normal functions of an organism/part of the body/cell/tissue/organ is impaired/disturbed.

(ii)Symptom: Any observable effect on an organism: Caused by the presence and irritation of a disease-causing agent/pathogen.

(b)(i) Physical barriers:

(i) Skin

(ii) Hairs

(iii) Cuticle

(iv) Epidermis

(v) Bark

(vi) Cell wall lining.

Chemical barriers:

(i) Mucus

(ii) Saliva

(iii) Tears

(iv) Gastric/ HCL and intestinal secretions

(v) Phenolic compound

(vi) Gums

(vii) Tannins

(viii) Wax

(ix) Oily secretions! sebum

(ii)How vaccination protects the body:The vaccine/attenuated pathogen is administered into the body. The body responds by producing copious antibodies. The next time the body is exposed to the same antigen/infection/pathogen antigen, the memory cells allow a more rapid and heightened/vigorous response to antibody production. Protection of the body against future infections.

(c) Differences between antibodies and antigens

(I) Antibodies is a protein molecule. Antigens May not be a protein molecule

(ii) Antibodies is Produced in response to a particular foreign substance/antigen while antigens Stimulates formation of antibodies

(iii) Antibodies Usually found in the plasma fluid of the blood,antigens are Usually produced in/introduced into the body.

(iv) Antibodies are Protective in functions, antigens Leads to an immune response/immunity.

(d) Causative Agent:

(i)Malaria: Plasmodium vivax/Plasmodium/malaria/species

(ii)Cholera: Vibrio cholera.

(ii)AIDS: Human Immuno-deficiency virus/HIV