☀️ • Lesson 1.3 : Plant and Human Nutrition (Bio) Flashcards
This lesson covers photosynthesis, leaf structures, human diets and all about the digestive system. Prepare for a big, crucial topic!
Describe Photosynthesis
Photosynthesis Is the process by which plants synthesize carbohydrates from raw materials using energy from light.
State the word equation for photosynthesis
Carbon dioxide + water → glucose + oxygen
(In the presence of light and chlorophyll)
What is chlorophyll and its function?
Chlorophyll is a green pigment that is found in chloroplasts, that transfers energy from light into energy in chemicals for the synthesis of carbohydrates.
What is the balanced symbol equation for photosynthesis?
6CO2 + 6H2O → C6H12O6 + 6O2
What is starch used for in plants?
Starch is used as an energy store
What is cellulose used for in plants?
Cellulose is used to build cell walls
What does glucose do for plants?
Glucose is used for respiration to provide energy
What is sucrose used for in plants?
Sucrose is used for transport in the phloem
Why do plants make nectar?
Nectar attracts insects for pollination
Why are nitrate ions important for plants?
Nitrate ions help plants make amino acids.
Why are magnesium ions important for plants?
Magnesium ions help plants make chlorophyll.
How do light, CO₂, and temperature affect photosynthesis?
More light, CO₂, and heat = faster photosynthesis.
What happens to gas exchange in aquatic plants in light and dark?
In light: Take in CO₂, release O₂.
In dark: Take in O₂, release CO₂.
Why do leaves have a large surface area and are thin?
Large surface area = more light for photosynthesis.
Thin shape = shorter distance for gases to move in and out.
What structures in the leaf help with gas exchange?
Stomata: Openings for CO₂ in and O₂ out.
Guard cells: Control the opening/closing of stomata.
What structures in the leaf help with photosynthesis?
Chloroplasts: Contain chlorophyll for photosynthesis.
Palisade mesophyll: Main site for photosynthesis.
What structures in the leaf help with water and nutrient transport?
Vascular bundles: Contain xylem and phloem for transport.
Xylem: Carries water.
Phloem: Transports nutrients.
What is a balanced diet?
A diet that includes all essential nutrients in the right amounts for health and energy.
What causes scurvy and rickets?
Scurvy: Lack of vitamin C — causes weak gums & skin.
Rickets: Lack of vitamin D — causes weak bones.
What are the main sources and importance of carbohydrates?
Sources: Bread, rice, pasta, potatoes.
Importance: Provides energy for the body.
What are the main sources and importance of fats and oils?
Sources: Butter, oils, nuts, avocados.
Importance: Energy storage, insulation, and protection for organs.
What are the main sources and importance of proteins?
Sources: Meat, fish, eggs, beans.
Importance: Needed for growth and repair of tissues.
What are the main sources and importance of vitamins C and D?
Vitamin C: Found in citrus fruits (needed for healthy skin and gums).
Vitamin D: Found in fish, eggs, sunlight (needed for strong bones).
What are the main sources and importance of calcium and iron?
Calcium: Found in milk, cheese (needed for strong bones & teeth).
Iron: Found in red meat, spinach (needed for red blood cells).
What are the main sources and importance of fibre (roughage)?
Sources: Whole grains, fruits, vegetables.
Importance: Helps with digestion and prevents constipation.
Why is water important in the diet?
Water helps with digestion, transport of nutrients, and temperature control.
What is the correct order of the alimentary canal?
Mouth → Oesophagus → Stomach → Small intestine (duodenum → ileum) → Large intestine (colon → rectum → anus)
What is the function of the salivary glands, and where are they found?
Function: Produce saliva with enzymes (ex. amylase) to start digestion.
Location: In the mouth, near the jaw and cheeks.
What is the function of the pancreas, and where is it found?
Function: Produces enzymes for digestion and insulin for blood sugar control.
Location: Below the stomach, near the small intestine.
What is the function of the liver, and where is it found?
Function: Produces bile to break down fats and removes toxins.
Location: Upper right side of the abdomen, above the stomach.
What is the function of the gall bladder, and where is it found?
Function: Stores and releases bile to help digest fats.
Location: Beneath the liver.
Describe Ingestion
Ingestion — the taking of substances, ex. Food and drink, into the body.
Describe Digestion
Digestion — the breakdown of food
Describe Absorption in the digestive system
Absorption — the movement of nutrients from the intestines into the blood
Describe Assimilation
Assimilation — uptake and use of nutrients by cells
Describe Egestion
Egestion — the removal of undigested food from the body as faeces.
Why is physical digestion important?
It increases the surface area of food, making it easier for enzymes to act.
What is chemical digestion?
The breakdown of large, insoluble molecules into small, soluble molecules using enzymes.
Why is chemical digestion important?
It produces small, soluble molecules that the body can absorb into the bloodstream.
What does the amylase enzyme do?
Amylase breaks down starch to simple reducing sugars.
Tip : Remember Amylase—Amylum (Starch)
What does the protease enzyme do?
Proteases break down protein to amino acids.
Tip : Remember Protease—Protein
What does the lipase enzyme do?
Lipase breaks down fats and oils to fatty acids and glycerol.
Tip : Remember Lipase—Lipids (Fats)
Where is amylase secreted, and where does it act?
Secreted by: Salivary glands & pancreas.
Acts in: Mouth & small intestine.
Function: Breaks down starch into sugars.
Where is protease secreted, and where does it act?
Secreted by: Stomach & pancreas.
Acts in: Stomach & small intestine.
Function: Breaks down proteins into amino acids.
Where is lipase secreted, and where does it act?
Secreted by: Pancreas.
Acts in: Small intestine.
Function: Breaks down fats into fatty acids & glycerol.
What are the functions of hydrochloric acid in the stomach?
It kills harmful microorganisms in food, and provides an acidic pH for protease enzymes to work properly.
Why is bile important for digestion?
It neutralizes stomach acid in the duodenum, creating the right pH for enzyme action.
How does bile help with fat digestion?
Bile emulsifies fats, breaking them into smaller droplets to increase surface area for enzyme action.
