BDSC Science year 9 Final Exam

What is the process of respiration in living organisms?

Respiration is the process of converting glucose into energy, which comes in two states: aerobic and anaerobic.

Write the equation for respiration

Glucose + oxygen → energy + carbon dioxide + water.

Why does heart rate increase during exercise?

During exercise, the body needs more energy, so the heart must pump faster to transport glucose, oxygen, CO2, and water more frequently to and from the cells.

What is the function of the vena cava

The vena cava is a large vein that carries blood to the heart from other areas of the body.

What do arteries and veins do?

Arteries carry blood away from the heart, while veins carry blood to the heart.

Define systolic and diastolic blood pressure.

Systolic blood pressure is when the heart contracts and creates larger pressure on artery walls (normal range 90-120). Diastolic blood pressure is when the heart relaxes and there is less pressure on the artery walls (normal range 60-80).

Describe the role of the alveoli in the lungs.

The alveoli are thin saclike structures where gas exchange happens; CO2 is removed from the blood into the alveoli and O2 moves into the blood.

What happens during an asthma attack?

During an asthma attack, the muscle wall contracts, and the lining of the airways becomes swollen and inflamed, causing narrowing of the airways and increased mucous secretions.

What are the main functions of the liver, gallbladder, and pancreas in digestion?

The liver creates bile, the gallbladder stores bile and releases it, and the pancreas creates enzymes and insulin.

List the food groups and their main functions.

Carbohydrates: Release energy

Proteins: Help you grow and cell repair

Fats: Provide energy, help absorb vitamins, and maintain warmth

Minerals: Build bones, influence muscle and nerve function, regulate water balance

Vitamins: Help the body concentrate and function

Water: Maintain hydration

Fibre: Regulate blood sugar levels and bowel function

What is a pathogen and give three examples

A pathogen is an organism or biological agent that can cause a disease. Examples include Virus Bacteria Fungi

Describe the process of immunisation

Immunization involves introducing a weakened version of a pathogen to the body through vaccination. The body prepares antibodies to counter the pathogen, and leftover antibodies will destroy any future pathogens.

What is the role of the pancreas?

The pancreas has both exocrine and endocrine functions, producing digestive enzymes and hormones to regulate blood sugar levels.

What digestive enzymes does the pancreas produce?

Amylase, lipase, and proteases (such as trypsin and chymotrypsin).

What hormones does the pancreas produce?

Insulin, glucagon, and somatostatin

What is immunization?

Immunization is the process by which an individual is made immune or resistant to an infectious disease, typically by the administration of a vaccine.

How is immunization helpful in general health

Immunization prevents diseases, reduces disease spread, protects vulnerable groups, lowers healthcare costs, and improves quality of life.

What is the green substance stored in the gallbladder?

Bile.

Why is BMI not a good indicator of health?

BMI does not account for muscle mass, fat distribution, age, sex, or overall health factors.

What does the large intestine digest?

The large intestine does not digest food; instead, it absorbs water and stores food for a short period before it leaves the body.

What is the order of respiration?

Respiration involves glucose and oxygen being converted into energy, carbon dioxide, and water. The process generally follows these steps:

1. Oxygen is transported to cells.

2.Glucose is converted into energy within cells.

3.Carbon dioxide and water are produced as by-products and transported out of cells.

Path of de-oxygenated blood

Lungs -- Left Atrium -- Left Ventricle -- Cells

Select the best definition for a healthy diet.

A healthy diet is one that contains a balanced amount of food from each food group, providing necessary nutrients for healthy growth and activity.

Describe two common causes of high blood pressure and explain how to reduce blood pressure.

Cause 1: Unhealthy Diet - Consuming too much salt, saturated fats, and cholesterol can lead to high blood pressure.

Cause 2: Lack of Physical Activity - Physical inactivity can lead to weight gain and increased blood pressure.

HOW TO FIX: Engage in regular physical exercise (30 minutes most days) and adopt a balanced diet rich in fruits, vegetables, whole grains, and lean proteins, while reducing salt, saturated fats, and cholesterol to maintain a healthy weight and lower blood pressure.

What is Matter

Something that takes up mass and volume, making up everything.

Define a Solid

State of matter with tightly packed particles, fixed shape and volume. Particles can vibrate in place. Examples: Ice, Metal, Wood.

Define Liquid

State of matter with loosely arranged particles, fixed volume but variable shape. Particles can move from one place to another. Examples: Water, Gasoline, Mercury.

Define Gas

State of matter with widely spaced particles, no fixed shape or volume. Particles move freely in random directions. Examples: Air, Oxygen, Carbon Dioxide.

Define Mass

Measure of the amount of volume in an object. The greater the mass, the more matter it contains and the heavier it is.

What is Volume

Amount of space an object occupies.

What is Density

Measure of how much mass is contained in a given volume. Solids are the most dense, followed by liquids, then gases.

Melting

Process of a solid becoming a liquid.

Freezing

Process of a liquid changing to a solid.

Boiling

Rapid change of a liquid to a gas by adding lots of heat.

Evaporation

Slow change of a liquid to a gas at lower temperatures.

Sublimation

Change of a solid directly to a gas. Examples: Iodine, Dry Ice (frozen CO2).

Conduction

Heat transfer through direct contact between objects, flowing from hotter to cooler objects.

Convection

Heat transfer through the movement of a fluid, such as air or water, where warmer fluids rise and cooler fluids sink.

Radiation

Heat transfer through the emission and absorption of electromagnetic waves without the need for a physical medium.

Heat

Transfer of thermal energy from a hotter object to a cooler one, driven by temperature difference.

Temperature

Measure of the average kinetic energy of a substance, indicating the hotness of the substance.

Thermal Energy

Form of energy due to an object's temperature.

Insulation

Using materials to prevent heat transfer between objects by conduction, convection, or radiation.

Dry Ice

Solid carbon dioxide at -79 degrees Celsius, changing from solid to gas by absorbing thermal energy.

Convection Current

Constant cycle of warmer fluid rising and cooler fluid sinking, occurring in liquids and gases.

Heat Transfer Sources

Natural sources like volcano/sun, man-made sources like lighter/heater, and nuclear energy.

Thermal Conductors

Objects with the ability to transfer heat energy efficiently, such as metals like steel or copper.

Thermal Insulators

Objects that resist heat conduction, such as polystyrene and plastics.

Substance Heating

Adding energy to a substance, causing particles to move more and change states.

Independent Variable

An independent variable is exactly what it sounds like. It is a variable that stands alone and isn't changed by the other variables you are trying to measure. For example, someone's age might be an independent variable.

Substance Cooling

Removing energy from a substance, causing particles to slow down and change states.

What minimizes heat loss?

silvered surfaces

Changing States of Matter

Matter can change from one state to another by gaining or losing heat energy, with specific temperature points for state changes.

Light

A form of energy visible to the human eye.

White Light

Light composed of a spectrum of colors.

Reflection

Bouncing of light off a surface.

Incident Ray

Ray of light hitting a surface.

Reflected Ray

Ray of light bouncing off a surface.

Angle of Incidence

Angle between incident ray and normal line.

Angle of Reflection

Angle between reflected ray and normal line.

Normal Line

Line perpendicular to the surface at the point of incidence.

Concave Mirror

Mirror with shiny surface on the inside curve.

Convex Mirror

Mirror with shiny surface on the outside curve.

Laws of Reflection

Angle of incidence equals angle of reflection.

Refraction

Bending of light as it passes through different media.

Primary Colors of Light

Red, Green, Blue; cannot be made by mixing.

Secondary Colors of Light

Colors made by mixing primary colors.

Diverging Lens

Lens that spreads light rays apart.

Converging Lens

Lens that focuses light rays to a point.

Gravitational Potential Energy

Energy stored due to an object's position in a gravitational field.

Measurement Units

Standard units used for quantifying physical quantities.

Zero Error

Difference between measured value and true value.

Speed of Light

Approximately 3.0 x 10^8 m/s in vacuum.

Spectrum of Colors

Range of colors produced by light dispersion.

Microscopes / Magnifying Glass

Instruments that magnify small objects using lenses.

Color Absorption

Objects absorb all colors except their own.

Light Source

Object that emits or produces light.

Curved Mirrors

Mirrors that are either concave or convex.

Plane Mirror

Flat mirror that reflects light without distortion.

SI Prefixes

Standardized prefixes for metric units.

Formula for Gravitational Potential Energy

Ep = m g h.

Acceleration Due to Gravity

Constant at approximately 10 m/s².

Kinetic Energy

Energy associated with motion of objects.

Kinetic Energy Formula

Ek = 0.5 m v².

Air Resistance

Opposing force when moving through air.

Speed

Change in distance over change in time.

Speed Measurement

Measured in meters per second (m/s).

Prism Spectrum

Different colors bend differently through a prism.

Cornea

Transparent front part of the eye.

Pupil

Dark hole allowing light into the eye.

Iris

Colored part controlling light entry into pupil.

Lens

Bi-convex disc focusing light onto retina.

Retina

Layer of light-sensitive cells at the eye's back.

Optic Nerve

Carries visual information to the brain.

Translucent

Allows light to pass but not clear images.

Opaque

Does not allow light to pass through.

Refracted Ray

Light ray that has changed direction in a medium.

Energy Transfer

Movement of energy through different forms.

Dependent Variable

the variable that changes as a result of the independent variable manipulation. It's the outcome you're interested in measuring, and it "depends" on your independent variable. In statistics, dependent variables are also called: Response variables

Controlled Variable

A controlled variable is a component kept constant in a scientific experiment to ensure the accuracy and reliability of the results. It is a key factor in the scientific method, as it allows researchers to isolate the effect of the independent variable on the dependent variable.