BIOLOGY AND ENERGY YEAR 8 EXAM.

BIOLOGY AND
ENERGY
YEAR 8 EXAM

 Biology and Energy
 1. a) Energy has led to the production of
electricity.
 b) Energy has promoted high
infrastructure and has reduced the cost of
buying expensive materials
 c) It has also led to an increase in the
number of producers in an ecosystem.
 2. Work- to exert effort in order to
accomplish something.
 3. a) kinetic energy- Energy on the motion
of a body.

 b) Heat energy- Energy that reflects the temperature
difference between two systems.
 c) Light energy- radiant energy which is visible to the
human eye.
 d) Sound energy-Energy where sound waves travel
through the air or another medium.
 e) Electrical energy- energy which results from running
appliances.
 f) Potential energy- energy exerted on the position of
an object.
 g) Gravitational energy-Energy associated with gravity
and involves attraction between two objects.
 h) Elastic potential energy- Energy that results when an
object is released moves faster and depends on the
position of the object.

 4. A car has high kinetic energy while the blue
Honda has the highest gravitational energy. Due to
the force of gravity care moving up on a mountain
will have greater kinetic energy than a blue Honda
which moves on a flat surface thus exhibiting
potential energy.
 5. i) Gravitational energy- a type of potential energy
where objects are pulled on the center of the earth.
 ii) Chemical energy - energy stored on the chemical
form to be used later like in battery
 iii) Elastic energy- energy applied on objects at rest.
The objects are pushed or pulled to release energy.
 iv) Sound energy – energy that on an object before
it is interfered with.

 6. When a body falls from a high place, the potential
energy is decreased as the object falls to earth. At the
highest point potential energy is at maximum and the
kinetic energy is zero and when it reaches the ground
the potential energy is zero while the kinetic energy is
at maximum.
 7. a) A piece of chocolate cake- chemical potential
energy
 b) A stretched spring- Elastic potential energy
 c) A glass of cola- chemical potential energy
 d) An empty coffee mug on a table- Elastic potential
energy
 e) A teaspoon of sugar- Elastic potential energy
 f) A cardboard box- Elastic potential energy
 g) A 9-volt battery- chemical

 h) A painter on top of a ladder-
gravitational energy
 i) A banana- Elastic potential energy
 j) A squashed tennis ball- gravitational
 8 a) Bond formation
 b) Bond breaking
 9. Energy transformation occurs when
energy is converted from one form to
another while energy transfer is the
transfer of energy from one place to
another.

 10 a) light energy. Chemical -Electrical
energy¬¬–Heat energy – Light energy
 b) Heat energy. Potential- kinetic- light –Heat
energy.
 c) Heat energy. Thermal – light –heat energy
 d) Light energy. Chemical energy- heat – light
energy
 e) Heat energy. Geothermal- electrical – heat
energy f) Chemical – electrical – sound/heat
energy
 g) Chemical-potential energy- electrical – light
energy.
 h) Chemical –mechanical- heat energy

 11. It states that the total energy of an isolated system
is constant. Energy is neither created nor destroyed
and thus it can be transformed from one form to
another or transferred from one system to another.
 12. Kinetic energy
 13. Heat energy
 14 Energy efficiency is the amount of work done
compared to the energy used during that certain
activity.
 15 Efficiency, N = Work done/energy spent
 16.a) 1000J -600J = 400J

 b) {400J/1000J X100%}
 = 40%.

 17. Non-renewable sources of energy do not replenish
in a short period compared to renewable sources.
 18. the more the stars the higher the saving cost.
 19 i) Ensuring the windows and attics are well
insulated.
 ii) Plant shade trees around the home.
 iii) Scheduling an energy audit for more expert advice.
 iv) Use of compact fluorescent lamps v) Starting a
composite pile
 vi) Installing a solar panel
 vii) Install a storm door
 viii) Buying Energy star products.
 20. a) Convection- Heat transfer in liquids.

 b) Conduction- heat transfer in solids
 c) Radiation- transfer of heat in gases.
TOPIC 2: CELLS (CHAPTER 2)
 1 – plasma membrane
-vacuoles
 2-chloroplasts -cell wall
- stem cells
 3. Similarities between plant and animal cells
- Both have eukaryotic cells that contain DNA.
-Both have undergone mitosis and meiosis.
-Both have mitochondria
- Both have vacuoles
-Both have cell structures called organelles which are
responsible for cellular operation.

 Differences between plant cells and animal cells
Animal cells
 Have various sizes and are irregular in shape
 Store energy in the form of carbohydrates
 Have centrioles
 Have no cell walls
Plant cells
 Have similar sizes and also have a regular shape
 Store energy in the form of starch
 Have no centrioles
 Have cell walls

 Similarities between fungi and bacteria
cells
- Both have cell walls
- Both undergo aerobic respiration
- Both possess cell membranes
composed of phospholipids
 Some yeasts and most bacteria
reproduce through binary fission

 Differences between bacterial and fungal cells
Bacteria
 Have no nucleus (prokaryotic)
 Bacteria are unicellular organisms
 Grow well around neutral pH values
 Sterols are absent in cell membrane
Fungi
 Have nucleus (Eukaryotic)
 Fungi are multicellular organisms
 Fungi grow best at around slightly acidic pH
values
 Sterols are present in the cell membrane

 4. a) Nucleus - the center of the cell it’s
the base of information.
 b) Ribosome- creates proteins
 c) Mitochondria- produce energy through
cellular respiration.
 d) Cell membrane- separates cell
contents from the environment.
 e) Vacuole- contains water or food.
 f) chloroplast- creates glucose
 g) Cell wall- protects the inner parts of
the cell.

 5. 1 GLUCOSE +6 O2  6 CO2 +6 H20+ 38 ATP
 6. Mitochondria.
 7. 6 CO2 + 6 H2O  C6H12O6 + 6O2
Carbon dioxide water Sugar Oxygen
 8. Leaf cells. Organelle - chloroplasts.

 9. Specialized are those cells that perform
only one function.
 Examples
 - Muscles cells
 - Red blood cells
 - Nerve cells
 - White blood cells
 10. Cell theory states that all living
organisms are made up of cells and their
products, new cells are created by old cells
dividing into two and cells are the basic
blocks of life.

 11. Unicellular are those organisms one cell such as yeast while
Multicellular is those with many cells like animals.
 Part Functions
 Eyepiece The lens which is used to look through an object
 Course adjustment knob Brings to bring images onto a focus
 Fine adjustment knob Used to bring images to a sharp focus.
 Nosepiece Hold the objective lens and can be rotated easily
 Stage Platform where slides are kept
 Mirror Reflects light on to the specimen
 Objective lens Enables good resolution on magnification
 Iris diaphragm Used to vary the intensity of the cone of light
that is projected upward into the slide
 Arm Supports the tube and also connects it to the base
 Base The bottom of a microscope used for support.

13
Eye piece
 5X
 10X
 100X
Objective
 10X
 20X
 10X
Total magnification
 50X
 200X
 1000X

 15. A - It has one membrane, plasma
membrane which encloses the other parts.
 16. a) Mitochondria-converts glucose to ATP
during respiration.
 b) Ribosome- Sites for protein synthesis
 c) Lysosomes- breakdown materials.
 d) Golgi bodies- packages proteins for
transportation.
 e) Cell membrane – border guard of the cell.
 f) Nucleus – has a nucleolus that makes RNA
and ribosome.
 17. Cell tissueorgan 

 Topic 3(SURVIVING)

 1. a) Red blood cells – carry oxygen
around the body
 b) Plasma- fluid in which blood cells are
transported through the body
 c) White blood cells- cells that get rid
the body of foreign particles.
 d) Platelets – prevents blood clotting.

 3. Pulmonary veinaortavena cavapulmonary
artery
 4. To prevent the backflow of blood.
 5. Right side and left side
 6. The thick side pumps blood to all body parts
while the thinner ventricle pumps to the heart.
 7. A gaseous exchange takes place in the through
alveolus. Oxygen is inhaled from the air into blood
capillaries and then it moves to all tissues in the
body during the process carbon dioxide is is
directed to capillaries and then is exhaled through
the bronchi. It occurs at the lungs in the alveoli.
 8. The process through which oxygen is taken in
the body to produce energy.

 9. When you breathe in, the chest cavity expands and
reduces the pressure of the air causing the air in the lungs
removed through the track. When exhalation takes place the
chest cavity contracts increasing air pressure causing the air
in the lungs expelled through the upper tract.
 10.
Nostrilstracheatracheolesbronchusbronchiolesalveolilu
ngs
 11. During breathing in, muscles contract the diaphragm
flattens enlarging the chest cavity rib muscles contracts
increasing the chest volume, air passes from high pressure
outside the lungs to the low pressure inside the lungs.
 12. Prevents food from entering the trachea during
swallowing.
 13. Diaphragm controls breathing system during inhalation,
it contracts and flattens while during exhalation, it raises the
ribs are lowered and the volume decreases.

 14. a) In physical digestion food is physically
broken down into smaller pieces while in
chemical digestion various chemicals break down
food into simpler and simpler molecules.
 b) in this mechanical digestion, it happens or
occurs at the mouth. The teeth grind, cut and
break food into smaller particles so as to increase
the surface area of the food digestion at the
stomach
 c)in chemical digestion two chemicals are used
acids and enzymes. Amylase is used in the mouth
which breaks down sugar and starches. Food is
torn to smaller particles to allow amylase and
hydrochloric acid to do their task appropriately.

 15

 17. Villi
 18. Colon
 19. Proteins
 20. a) phloem is used in transporting food and organic
materials while xylem is used in the transportation of
water and nutrients.
 b) Pulmonary artery pumps blood to the lung while the
pulmonary vein receives blood from the lungs.
 c) Arteries carry oxygenated blood while veins carry
deoxygenated blood.
 d) Ventricles have no valves while atriums have.
 e) Oxygenated blood is blood rich in hemoglobin while
deoxygenated is a blood rich in carbon dioxide.
 f) The left side is thicker while the right side is thinner


 21

 Mouth – where a breakdown of food starts. It
produces salivary amylase which is responsible for
the breakdown of starch.
 Esophagus - has contractions called peristalsis which
allows the smooth flow of food to the stomach.
 Stomach - where food mixes with enzymes
completely.
 Small intestines- of food take place.
 Colon- reabsorption of indigestible water and
mineral salts.
 Liver- produces bile juice.
 Rectum – sores rectal contents before they are
realized.