Nutrition & Respiration

what does a balanced diet include?

appropriate proportions of carbohydrate, lipid, fibre, protein, vitamins, minerals, water

what is the function of carbohydrates?

the body's main source of energy (for respiration)

what is the function of protein?

growth (creating new cells) and the repair of damaged tissues and enzymes

what is the function of lipids?

long-term energy storage, insulation and protection of organs

what is the function of vitamin A?

maintaining good vision, supporting immune function, and maintaining healthy skin

what is the function of vitamin C?

maintaining healthy connective tissue, skin, gums, and blood vessels

what is the function of vitamin D?

absorption of calcium in the small intestine, which are necessary for developing and maintaining strong bones and teeth

what is the function of calcium?

building and maintaining strong bones and teeth, aiding in blood clotting

what is the function of iron?

production of haemoglobin, protein in red blood cells responsible for transporting oxygen around body.

what is the function of water?

acting as the primary medium for chemical reactions, transport, and waste removal

what is the function of fibre?

aiding digestion and maintaining bowel health

what are some sources of carbohydrates and what happens if you don’t have enough of it?

bread, pasta, potatoes and sugars- fruits, milk

can lead to fatigue, low blood sugar

what are some sources of protein and what happens if you don’t have enough of it?

meat, eggs, dairy and beans, lentils, soy

can lead to stunted growth, muscle loss

what are some sources of lipids and what happens if you don’t have enough of it?

butter, pork, salmon, olive oil

can lead to poor temperature regulation

what are some sources of vitamin A and what happens if you don’t have enough of it?

liver, egg yolks (fat soluble)

can lead to night blindness

what are some sources of vitamin C and what happens if you don’t have enough of it?

oranges, lemons, limes

can lead to scurvy or anaemia

what are some sources of vitamin D and what happens if you don’t have enough of it?

sunlight, salmon, beef liver

can lead to rickets

what are some sources of calcium and what happens if you don’t have enough of it?

milk, cheese and yoghurt

can lead to weak bones and teeth, rickets

what are some sources of iron and what happens if you don’t have enough of it?

beef, lamb, lentils, broccoli

can lead to iron deficiency (anaemia)

what are some sources of fibre and what happens if you don’t have enough of it?

whole-wheat bread, pasta, oats

can lead to constipation or piles

how do energy requirements vary with activity levels, age and pregnancy?

based on metabolic needs for activity, growth, and tissue maintenance

example, children and pregnant women need more energy

1-Mouth

2- oesophagus

3-Liver

4-Gallbladder

5-Pancreas

6-Small intestine

7- appendix

8-salivary glands

9-stomach

10- bile duct

11-large intestine

12-rectum

13-anus

what is the function of the mouth in digestion?

begin both mechanical and chemical digestion of food (ingestion)

teeth- grinds food

tongue- helps mix food with saliva

what is the function of the stomach in digestion?

mechanically churn food into a liquid called chyme and begin the chemical digestion of proteins

the HCl in the stomach kills bacteria

what is the function of the small intestine in digestion?

carbs digestion- pancreatic amalyse breaks down starch and maltase breaks down maltose into glucose

protein digestion- trypsin breaks down polypeptides into amino acids

lipid digestion- lipase breaks down fats into fatty acids and glycerol

bile action- bile produced in liver and stored in gallbladder is released to emulsify fats and neutralise stomach acid to provide optimum alkaline pH for enzymes

what is the function of the large intestine in digestion?

The colon absorbs water, mineral ions and vitamins

Egestion occurs- process of passing out food that hasn’t been digested/ absorbed (faeces) through anus

rectum stores faeces until ready to be expelled

what is the function of the pancreas in digestion?

produces and secretes pancreatic juice into the duodenum via the pancreatic duct

in pancreatic juice there’s amylase, trypsin, lipase and sodium hydrogencarbonate

what is the function of the gullet in digestion?

transports food from the mouth to the stomach using peristalsis

peristalsis are wave-like muscular contractions that push the food bolus downward

list all the enzymes and the substrates they break down

amylase- starch to maltose

maltase- maltose to glucose

proteases- proteins to amino acids

lipases- lipids to fatty acids and glycerol

where is bile produced and stored?

it is produced by the liver and stored in the gall bladder

what is the role of bile in digestion?

it emulsifies fats and neutralises stomach acid

how does bile emulsify fats?

Bile break down large fat droplets into many smaller droplets

makes much larger surface area for the enzyme lipase to work on- digestion of lipids happens faster

Explain the method to investigate the energy content in a food sample

1- Thermometer

2- Boiling-tube

3- Water

4- Scale

5- Burning food

6- Mounted needle

• Measure fixed volume of water into boiling tube

• Record initial temperature of water

• Weigh food sample

• Attach food to mounted needle

• Burn food sample with flame

• Hold burning food under boiling tube of water

• Allow food to burn completely

• Record final temperature of water

• Reweigh food/ash to find mass burned

How do you calculate the energy transferred in the energy content of a food sample?

Energy = mass of water x 4.2 x temperature change

4.2 = specific heat capacity of water

how do you calculate energy per gram of food?

energy per gram = energy transferred / mass of food burned

what are the control variables in the food energy content experiment?

• Volume of water

• Distance between food and tube

• Starting temperature

• Same apparatus

What are the sources of error in the food energy content experiment?

• Heat lost to surroundings

• Heat absorbed by apparatus

• Food may not burn completely

How could you improve the accuracy of food energy content experiments?

• Use a lid on the tube

• Use a metal calorimeter

• Insulate the apparatus

• Stir the water

what is respiration?

the chemical reactions in cells that break down nutrient molecules (glucose) to release energy (ATP) for metabolism

what is the difference between aerobic and anaerobic respiration?

oxygen required: Yes, No

glucose breakdown: complete, incomplete

energy yield: high, low

location in cell: cytoplasm and mitochondria, cytoplasm

what is the word equation for aerobic respiration?

Glucose + Oxygen—> Carbon dioxide + Water (+ Energy)

what is the balanced symbol equation for aerobic respiration?

C₆H₁₂O₆ + 6O₂ —> 6CO₂ + 6H₂O

what is the word equation for anaerobic respiration in animals?

glucose—> lactic acid (+little ATP)

what is the word equation for anaerobic respiration in plants?

glucose —> ethanol + carbon dioxide (+little ATP)

what is the method for investigating carbon dioxide production in respiration in living organisms?

1. Place germinating seeds in a boiling tube.

2. Add cotton wool to keep them in place.

3. Connect the tube so the gas produced passes into limewater.

4. Leave for some time.

the limewater turns cloudy.

What could you use as a control experiment for investigating respiration in living organisms?

Dead seeds (boiled seeds)

they do not respire—> shows carbon dioxide came from respiration, not another source

what is the method for investigating heat production in respiration in living organisms?

1. Place germinating seeds in an insulated flask.

2. Insert a thermometer.

3. Leave for a period of time.

4. Record the temperature change

Temperature increases

how is the small intestine adapted for absorption?

Each villus has microvilli

One cell thick

Rich network of blood capillaries

central lymph vessel

large number of epithelial cells

Explain the adaptation of the small intestine- “large number of epithelial cells”

provide energy via respiration for active transport of certain nutrients

Explain the adaptation of the small intestine- “central lymph vessel”

specialised for absorbing and transporting lipids

Explain the adaptation of the small intestine- “Rich network of blood capillaries”

maintains steep concentration gradient for faster diffusion

Explain the adaptation of the small intestine- “each villus has microvilli”

increases surface area

Explain the adaptation of the small intestine- “one cell thick”

short diffusion distance

Why do the number of live yeast cells decrease toward the end of beef production?

There is less glucose so there is a decrease in ethanol

How can you modify apparatus to measure rate of oxygen production more accurately?

Use a measuring cylinder

Why is there an oil layer in the experiment investigating temperature on rate of carbon dioxide production?

It keeps out oxygen so the yeast is sure to respire anaerobically

Explain how a deficiency in Vitamin D can lead to anaemia, mentioning calcium absorption.

Vitamin D is needed for calcium absorption

Without vitamin D, calcium absorption is reduced

Low calcium leads to weak bones and may affect iron absorption or blood formation

Reduced red blood cells —> anaemia

what is synthesis?

small food molecules are used to build large molecules