Year 8 Science: Master Chefs & Engineers Review

Flashcards to review key concepts from the Year 8 Scientists in Action Unit 2, covering Nutrition, Digestion, Food Tests, Metals, and Chemical Reactions.

Nutrients

Chemical substances required for the proper functioning of our bodies, including growth, repair, reproduction, and movement.

Carbohydrates

The body's main source of energy; examples include potatoes, bread, and rice.

Lipids

Nutrient that has roles as a secondary source of energy, an insulator, and in protecting internal organs; examples include butter, oils, and ghee.

Proteins

Nutrient needed to repair body tissues, make new cells, and replace old or worn-out cells; examples include meat, fish, and eggs.

Vitamins

Nutrient essential for many processes, such as preventing deficiency diseases and aiding body processes; examples include fruits and vegetables.

Minerals

Nutrient essential for many processes, such as normal bone growth/strength and a healthy nervous system; examples include fruits and vegetables.

Fiber

Adds bulk to your food and helps keep food moving through the gut, preventing constipation; examples include fruits, vegetables, and wholegrains.

Water

Supports chemical reactions within cells and blood relies on it to transport dissolved substances throughout the body; examples include water and juices.

Starch Test

Test using iodine solution to identify the presence of starch, indicated by a color change from orange/brown to blue/black.

Simple Sugar Test

Test using Benedict’s solution and heat to identify the presence of reducing sugars, indicated by a color change from blue to green, orange, or brick red depending on sugar concentration.

Lipid Test

Test using ethanol to identify the presence of lipids, indicated by a change from colorless to cloudy/milky.

Protein Test

Test using Biuret solution to identify the presence of protein, indicated by a color change from blue to purple.

Health

A state of physical, mental, and social well-being, and not merely the absence of disease or infirmity.

Deficiency Disease

Occurs when someone does not get enough of a specific vitamin or mineral, leading to poor health and problems in the body.

Malnutrition

Happens when a person is either extremely overweight or underweight due to eating too much, too little, or the wrong types of food.

Scurvy

A disease associated with Vitamin C deficiency, characterized by bleeding gums.

Rickets

A disease associated with Vitamin D deficiency, characterized by soft and bent bones.

Why is energy essential for life?

To fuel many different body processes such as growth, repair, reproduction and movement.

What factors affect a person's dietary energy requirements?

Age, gender, body size, level of activity, genes, and current body conditions (e.g. pregnancy, diabetes)

Digestion

The process in which large, insoluble molecules in food are broken down into smaller, soluble molecules that can be absorbed into the bloodstream.

Alimentary Canal

The channel or passage through which food flows through the body, starting at the mouth and ending at the anus.

Mechanical Digestion

The physical process of breaking food into smaller pieces without altering its chemical structure, occurring in the mouth and stomach.

Chemical Digestion

Involves breaking down food into simpler molecules using enzymes and other digestive chemicals, beginning in the mouth and continuing in the stomach and small intestines.

Enzymes

Biological catalysts that speed up chemical reactions such as breaking down of food, and are not used up or changed in these reactions.

Carbohydrases

Break down carbohydrates to simple sugars such as glucose; amylase is a type that breaks down starch into maltose.

Proteases

Break down proteins into amino acids.

Lipases

Break down lipids (fats) to glycerol and fatty acids.

Hydrochloric Acid in Digestion

Kills many harmful microorganisms ingested with food and creates the optimum acidic environment for stomach enzymes to function.

Bile's Role in Digestion

Neutralises stomach acid and emulsifies fats, breaking down large fat globules into smaller droplets to increase the surface area for enzyme action.

Optimum Temperature for Enzymes

The temperature at which enzymes work fastest; in the human body, this is typically 37°C.

Denaturation

When enzymes lose their shape due to high temperatures, preventing substrates from fitting into their active site, and is irreversible.

Exchange Surface

Any part of an organism that allows for the exchange of materials between the organism and its environment; examples include the alveoli in the lungs and the villi in the small intestines.

Villi

Found on the walls of the small intestine and have adaptations such as a vast network, thin walls, capillaries and lacteal to aid in faster absorption.

Corrosion

The gradual degradation or wearing away of materials as a result of chemical reactions with their environment.

Rusting

A specific type of corrosion that only affects iron or steel when exposed to oxygen and moisture, resulting in the formation of iron oxide (rust).

Hydrogen

When acids and metals react, they produce this gas and a salt.

Displacement Reaction

A reaction in which a more reactive metal will displace a less reactive metal from its compound.

Metal hydroxide and Hydrogen gas

When metals react with water they produce these two things…

Boiling point

The temperature at which a substance changes from liquid to gas (evaporates).

Displacement reaction

A reaction in which a more reactive substance displaces a less reactive substance.

Ductile

Can be stretched into wires.

Malleable

Can be hammered or pressed into different shapes.

Sparks or flames, Smell, Fizzing or a bang, Change in temperature, Formation of water, Formation of a precipitate, Colour change

A reaction is taking place as you witness this…