Everything here is for unit 5 of the Grade 10 Biology textbook: what the chapter covers, the short notes, practice questions with their answers, and the lesson video where one exists.
6
Cards
10
Practice questions on unit 5
94–152
The textbook pages for unit 5
Short notes for unit 5
The cards filed under this chapter on the Grade 10 Biology page. Open one at a time.
Blood Group
Antigen on RBC
Antibodies in Plasma
Can Receive Blood From
Group A
A
Anti-B
A, O
Group B
B
Anti-A
B, O
Group AB
A and B
None
A, B, AB, O
Group O
None
Anti-A and Anti-B
O
When you use it
Use to determine antigen and antibody combinations or blood transfusion compatibility.
Watch out
Group O red blood cells have no ABO antigens, making O a universal donor, while AB plasma has no ABO antibodies, making AB a universal recipient.
Drafted from Grade 10 Biology, pages 94-152, then checked twice before it went up
Enzyme
Source Gland / Organ
Digestive Reaction
Optimum pH
Salivary amylase (ptyalin)
Salivary glands
Starch + H2O -> Maltose
pH 7
Pepsin
Gastric glands (stomach)
Protein + H2O -> Polypeptides
pH 1 to 3
Pancreatic amylase
Pancreas
Starch + H2O -> Maltose
pH 7 to 8
Trypsin
Pancreas
Protein + H2O -> Peptides
pH 7 to 8
Pancreatic lipase
Pancreas
Fat + H2O -> Glycerol + Fatty acids
pH 7 to 8
Erepsin
Pancreas and small intestine
Peptides + H2O -> Amino acids
pH 7 to 8
Maltase
Small intestine
Maltose + H2O -> Glucose
pH 7 to 8
When you use it
Use to identify where specific nutrients are chemically broken down and the required pH environment.
Watch out
Bile contains no enzymes, it only mechanically emulsifies fat globules into droplets to increase surface area for lipase.
Drafted from Grade 10 Biology, pages 94-152, then checked twice before it went up
Cell Type
Normal Count
Life Span
Primary Function
Erythrocytes (RBC)
5 to 6 million per mm3
120 days
Transport oxygen and help transport CO2
Leukocytes (WBC)
5000 to 10000 per mm3
18 to 36 hours (some up to 1 year)
Defense and immunity
Platelets (thrombocytes)
250000 to 400000 per mm3
9 to 10 days
Blood clotting
When you use it
Use to compare the cellular components of blood by count, lifespan, and biological roles.
Watch out
Mature erythrocytes lose their nuclei to accommodate more hemoglobin, and platelets are non-nucleated cell fragments rather than complete cells.
Drafted from Grade 10 Biology, pages 94-152, then checked twice before it went up
Valve
Anatomical Location
Prevents Backflow Into
Tricuspid valve (Right AV)
Between right atrium and right ventricle
Right atrium
Bicuspid valve (Left AV, Mitral)
Between left atrium and left ventricle
Left atrium
Pulmonary semilunar valve
Between right ventricle and pulmonary artery
Right ventricle
Aortic semilunar valve
Between left ventricle and aorta
Left ventricle
When you use it
Use to identify valve locations and how they maintain one-way blood flow through the heart.
Watch out
Tricuspid valve is on the right side of the heart, while bicuspid (mitral) valve is on the left side.
Drafted from Grade 10 Biology, pages 94-152, then checked twice before it went up
Dentition Type
Dental Formula
Total Teeth
Adult permanent teeth
(2123/2123)×2
32
Child milk (deciduous) teeth
(2102/2102)×2
20
When you use it
Use to calculate the number and types of teeth in adult and child dentitions.
Watch out
Dental formula represents only one side of the upper and lower jaws, so the entire ratio must be multiplied by 2.
Drafted from Grade 10 Biology, pages 94-152, then checked twice before it went up
Part
What it does
Blood or filtrate
Glomerulus
A knot of capillaries where blood is filtered under pressure. Water, glucose, amino acids, salts and urea are pushed out. Blood cells and plasma proteins are too large to leave.
Blood
Bowman's capsule
The cup around the glomerulus. It catches the filtrate and passes it into the tubule, so it is the first stop on the filtrate route.
Filtrate
Afferent arteriole
Carries blood into the glomerulus. It is wider than the efferent arteriole, and that difference holds the pressure high enough to filter.
Blood
Efferent arteriole
Carries blood away from the glomerulus, then breaks up into the peritubular capillary network around the tubule.
Blood
Proximal convoluted tubule
Where most reabsorption happens. Glucose and amino acids are taken back completely under normal conditions, along with ions and much of the water. Drugs, toxins and ammonia are secreted into the filtrate here.
Filtrate
Loop of Henle
A hairpin dipping into the medulla. Water leaves the descending limb. Sodium and chloride ions leave the ascending limb, which holds water back, so the filtrate grows more dilute and the medulla around it turns salty.
Filtrate
Distal convoluted tubule
The fine tuning. Potassium and hydrogen ions are secreted into the filtrate while sodium, chloride and hydrogen carbonate ions are reabsorbed, holding blood pH and salt balance steady.
Filtrate
Collecting duct
Several nephrons drain into one. The last of the water is reabsorbed here under the control of antidiuretic hormone, which sets how concentrated the urine is.
Filtrate
Peritubular capillaries
The network wrapped around the tubule. Reabsorbed glucose, ions and water rejoin the blood here.
Blood
When you use it
Use it when labelling a nephron diagram, tracing what happens to the filtrate, or answering which part reabsorbs glucose and where the urine is concentrated. The filtrate route has five stops: Bowman's capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting duct.
Watch out
Students learn the labels in the order they are printed around the diagram, then write the afferent and efferent arterioles into the urine route. Those two carry blood and never filtrate. Keep the two paths apart: blood runs afferent arteriole, glomerulus, efferent arteriole, peritubular capillaries. The filtrate starts in Bowman's capsule rather than in the glomerulus, because the glomerulus is a knot of capillaries and the capsule around it is the first place the filtrate sits.
Practice questions on unit 5
10 multiple-choice questions written against this chapter, each with its answer and the reason. Try one before you open the answer.
Question 1
Which enzyme is found in human saliva to begin the chemical breakdown of starch into simpler molecules?
A.Pepsin
B.Salivary amylase
C.Lipase
D.Trypsin
Show the answer and why
Answer: B Salivary amylase
Why
Saliva contains salivary amylase (also called ptyalin), which begins the chemical digestion of starches in the oral cavity.
Question 2
According to the human dental structure, which chisel-shaped teeth at the front of the mouth are specialized for cutting food?
A.Incisors
B.Canines
C.Premolars
D.Molars
Show the answer and why
Answer: A Incisors
Why
Incisors are the eight chisel-shaped teeth at the front of the mouth designed specifically for cutting food.
Question 3
Which valve prevents the backflow of blood from the right ventricle into the right atrium?
A.Bicuspid valve
B.Aortic valve
C.Tricuspid valve
D.Pulmonary valve
Show the answer and why
Answer: C Tricuspid valve
Why
The tricuspid valve (right atrioventricular valve) separates the right atrium from the right ventricle and prevents backflow of blood.
Question 4
What is the normal average lifespan of human red blood cells (erythrocytes)?
A.18 to 36 hours
B.9 to 10 days
C.120 days
D.1 year
Show the answer and why
Answer: C 120 days
Why
Human erythrocytes (red blood cells) have an average lifespan of about 120 days in the bloodstream.
Question 5
How does the textbook distinguish between egestion and excretion in humans?
A.Egestion removes undigested food waste, while excretion removes metabolic wastes.
B.Egestion occurs only in plants, while excretion occurs only in animals.
C.Egestion eliminates urine, while excretion eliminates feces.
D.Egestion removes carbon dioxide, while excretion removes solid waste.
Show the answer and why
Answer: A Egestion removes undigested food waste, while excretion removes metabolic wastes.
Why
Egestion is the removal of undigested food residue remaining after digestion, whereas excretion is the process of getting rid of metabolic waste products formed inside cells.
Question 6
Why is the action of bile salts on large fat globules classified as physical digestion rather than chemical digestion?
A.Because it breaks chemical bonds inside fatty acids
B.Because it breaks down fat droplets into smaller droplets without breaking chemical bonds
C.Because it takes place entirely inside the stomach
D.Because bile salts contain active protein-digesting enzymes
Show the answer and why
Answer: B Because it breaks down fat droplets into smaller droplets without breaking chemical bonds
Why
Bile salts emulsify large fat globules into tiny droplets without breaking chemical bonds, which increases the surface area for enzymes like lipase to act chemically.
Question 7
During a heartbeat, what causes the first audible heart sound, Lub?
A.The closing of the semilunar valves during ventricular diastole
B.The closing of the atrioventricular valves during ventricular contraction
C.The rush of blood through the coronary arteries
D.The contraction of the muscular walls of the atria
Show the answer and why
Answer: B The closing of the atrioventricular valves during ventricular contraction
Why
The Lub sound is produced by the closing of the atrioventricular valves (tricuspid and bicuspid) during ventricular contraction (systole).
Question 8
A student in Addis Ababa learns that a person has blood group AB. Which antigens and antibodies are present in this person's blood?
A.Both A and B antigens on red cells, but no anti-A or anti-B antibodies in plasma
B.Neither A nor B antigens on red cells, but both anti-A and anti-B antibodies in plasma
C.Only A antigens on red cells and anti-B antibodies in plasma
D.Only B antigens on red cells and anti-A antibodies in plasma
Show the answer and why
Answer: A Both A and B antigens on red cells, but no anti-A or anti-B antibodies in plasma
Why
Individuals with blood group AB have both A and B antigens on the surface of their red blood cells, and their plasma contains neither anti-A nor anti-B antibodies.
Question 9
In the villi of the human small intestine, which route is used to absorb digested fats?
A.Directly into the blood capillary networks
B.Into the central lymph vessels called lacteals
C.Directly into the hepatic portal vein
D.Across the epithelial cells into the stomach lining
Show the answer and why
Answer: B Into the central lymph vessels called lacteals
Why
Monosaccharides and amino acids are absorbed directly into the capillary networks of the villi, whereas digested fats are absorbed into the lymph vessels called lacteals.
Question 10
How is inactive pancreatic trypsinogen converted into its active form, trypsin, in the digestive tract?
A.By hydrochloric acid in the stomach
B.By salivary amylase in the esophagus
C.By the enzyme enterokinase in the small intestine
D.By bile salts secreted from the gallbladder
Show the answer and why
Answer: C By the enzyme enterokinase in the small intestine
Why
When inactive trypsinogen reaches the small intestine, the enzyme enterokinase converts it into active trypsin to digest polypeptides.
The app holds 12 questions on this unit, marked as you go. These are the first 10.
The textbook pages for unit 5
Unit 5 runs from page 94 to page 152 of the Ministry of Education edition.
