Excretion and homeostasis
1.i) Ammonia is highly soluble in water and
requires a lot of water for excretion hence assists in
the removal of excess ammonia;
ii) All the glucose is reabsorbed at the proximal convoluted tubule;
(a) – Excretion;
- Osmo-regulation;
(b) – Glucose
- Amino acids;
(c) – Nephritis;
- Hepatitis A and B;
(a) Extra long loop of henle; Have fewer and smaller glomeruli;
(b) Salty food increased the salt concentration in blood;
Blood becomes hypertonic to kidney tubules;
more water is reabsorbed from kidney
tubules; hypertonic urine is thus produced;
(a) Glucose;
(b) The person was a sufferer of diabetes mellitus;
(c) Pancrease;
5.a) i)insulin;
ii) Diabetes mellitus;
b) Diuresis is a condition which is
characterised by production of large volumes of dilute urine;
6.i) urea;
ii) Triethylamine;
iii) Ammonia;
7.a) i) Fresh water; reject water
b) Reduces blood flow to the skin as more
blood is stored in the spleen, reducing heat loss
Through the skin;
8.a) Ultra filtration;
b) Selective reabsorption;
c) Proteins have large molecular weights hence not ultrafiltrated;
9.Produces sebum to keep hair and epidermis
supple and water proof; and protect skin against
Bacteria (through antiseptic substances);
10.a) Sweat produced does not evaporate due to high humidity;
b) Body does not cool hence more
sweat is produced leading to accumulation;
11.Diabetes mellitus
- Caused by failure of the pancreas to secrete enough insulin;
- High glucose concentration in the blood than normal;
Diabetes insipidus
- Inability of the pituitary gland to secret anti-duretic hormone;
- High concentration of solutes in blood;
Two processes through which plants excrete metabolic wastes: -
-Gaseous exchange;
-Transpiration;
-Shading leaves;
-Production of resins and gums;
Has got long loop of henle in order to
maximize water reabsorption thus conserving it;
14.i) urea;
ii) Triethylamine;
iii) Ammonia;
15.(a) i) Fresh water; reject water
b) Reduces blood flow to the skin as more blood
is stored in the spleen, reducing heat loss through
the skin;
16.a) Ultrafiltration;
b) Selective reabsorption;
c) Proteins have large molecular weights hence not ultrafiltrated
17.Produces sebum to keep hair and epidermis
supple and water proof; and protect skin against
Bacteria (through antiseptic substances);
18.a) Sweat produced does not evaporate due to high humidity
b) Body does not cool hence more
sweat is produced leading to accumulation
19.
Diabetes mellitusDiabetus insipidus
-Caused by failure of the pancreas to secrete enough insulin
-High glucose concentration in the blood than normal
- Caused by failure of the pancreas to secrete enough insulin
- High glucose concentration in the blood than
normal-Inability of the pituitary
gland to secret anti-duretic hormone
-High concentration of solutes in blood
Inability of the pituitary gland to secret anti-duretic hormone
High concentration of solutes in blood
Two processes through which plants excrete metabolic wastes: -
-Gaseous exchange
-Transpiration
-Shading leaves
-Production of resins and gums
a) A – medulla; B – Cortex;
b) Cortex;
22.a) Enhances more reabsorption of
water; leading production little but conc urine;
a) Aldosterone;
b) Loop of Henle;
c) Positive feed back;
- Reabsorption of unuseful substances in the kidney;
- Absorption of digested food from the ileum;
- Removal of metabolic waste products from kidney;
b) Pituitary gland;
c) Diabetes Inspidus;
26.a) - Afferent vessels are wider than effereal vessels;
- Presence of pores on capillary and Glomerula membrane;
- Highly coiled narrow capillaries to
reduce speed of flow of blood and increase;
pressure
b) Ammonia
c)i) Contractile vacuole
Malpigian tubules
28.- Deamination
- Detoxification
- Breakdown of haemoglobin
29.a)Deamination;
b)-Removal of excess amino acids;
-Availing of energy in the body;
30.a)diabetes insipidus;
b)antidiusetic hormones (ADH);
31.a) large quantities of dilute urine;
b) Small quantities of concentrated
urine ;(renal failure if habitual)
(a) Excretion — Separation and
elimination of waste products of metabolism from
bodies of living organisms:
Egestion; Removal of undigested materials
(b) Removes waste products metabolism to
best working of cells
(b) Small sized glomeruli;
to reduce ultra filtration longer loop of henle; to increase
reabsorption of water – conservation of water.
N.B – Reject 12(b) if 12 (a) is wrong.
34.(a) – Organisms whose body temperature
varies with the environmental temperature;
(b) – Reptilia- rej. Reptile;
- amphibia - rej. Amphibians;
Glomerulus;
Adaptations of part R
-Coiled to increase the surface area for
re-absorption of some glomerular filtrate
-Presence of numerous Mitochondria to
promote active transport of glucose, amino acids
-covered by dense network of blood capillary
for absorption of useful glomerular filtrate
Internal environment is the immediate surrounding of the body
cells while external environment is
the immediate surrounding of the organism
37.
•Radiation;
•Conduction;
•Convection;
•Evaporation;
B – Descending wing of loop of Henle;
D – Glomerula
b) Urea;
Ovary; accept ovules
Anthers;
40.a) Detoxification;
b) Liver;
c) Prevents ammonia from accumulating to
toxic levels; which would affect body functions;
d) Urea;
e) Excess amino acids are broken down to
form amino group; which is combined with
hydrogen atom to form ammonia;
f) It is transported to the kidney;
through the renal artery where it is excreted
41.a) platelets exposed to air rupture on damage tissues to release
Thromboplastin neutralizes heparin;
and activates prothrombin to thrombin;
Throbin activates the conversion of fibrinogen to
fibrin; which forms meshwork of fibres on the bruised surface;
b) blood clotting is the conversion of soluble
blood protein into a mass of tangled threads of
Insoluble protein;
while haemogglutination is the clumping
together of red blood cells; c)haemophilia;
42.a)i)glucose is completely reabsorbed at
proximal convoluted tubule back to blood stream;
ii) Protein has m
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