Stuff I Didn’t Know When Going Through Spec List

How does surface area to volume ratio affect the rate of movement of substances into and out of cells?

larger surface area to volume ratio increases the rate of diffusion

How does distance affect the rate of movement of substances into and out of cells?

shorter distance increases the rate of diffusion

How does temperature ratio affect the rate of movement of substances into and out of cells?

higher temperatures increase kinetic energy of molecules → increasing rate of diffusion

How does concentration gradient ratio affect the rate of movement of substances into and out of cells?

steeper concentration gradient = faster rate of diffusion

Define diffusion

the movement of molecules from high to low concentration

Define active transport

the movement of molecules from low to high concentration using energy (from respiration) and carrier proteins to pump molecules

Define osmosis

the movement of water molecules from a high to low water potential across a partially permeable membrane

How does varying light intensity affect the rate of photosynthesis?

More light gives energy for photosynthesis so rate increases till another factor limits it

How does varying carbon dioxide concentration affect the rate of photosynthesis?

raw material for photosynthesis, more CO₂ = faster rate up to a certain point

How does varying temperature affect the rate of photosynthesis?

enzymes control photosynthesis - if too cold, reactions are slow + if too hot, enzymes may denature

How is the leaf being broad an adaption for photosynthesis?

large surface area to absorb lots of light

How is the leaf being thin an adaption for photosynthesis?

so gasses have short diffusion distance

How is the upper epidermis an adaption for photosynthesis?

its transparent which allows light to reach the palisade cells

How are the palisade mesophyll cels an adaption for photosynthesis?

they are packed with chloroplasts to absorb light for photosynthesis

List 4 adaptions the structure of a leaf has for photosynthesis

• Leaf is broad

• Leaf is thin

• Upper epidermis is transparent

• Palisade mesophyll cells have lots of chloroplasts

What ions do plants require and why do they need them?

• Mineral ions = for growth

• Magnesium ions = for chlorophyll

• Nitrate ions = for amino acids

What does a balanced diet require? (7 bullet points)

• Carbohydrates

• Protein

• Lipids

• Vitamins

• Minerals

• Water

• Dietary fibre

what is the function of carbohydrates?

main energy source for respiration

what is the function of proteins?

growth + repair tissues

what is the function of lipids (fats + oils)?

insulation, energy store - but too much can lead to diabetes

what is the function and source of vitamin A?

function = needed for vision

source = carrots

what is the function and source of vitamin C?

function = important for healthy skin + gums

source = citrus fruits

what is the function and source of vitamin D?

function = helps calcium absorption for healthy bones + teeth

source = sunlight exposure

what is the function and source of minerals?

calcium = dairy products, important for strong bones + teeth

iron = red meat, important for forming haemoglobin in red blood cells

what is the function of water?

hydration, temperature regulation

what is the function and source of dietary fibre?

function = aids digestion + prevents constipation

source = whole grains

what is the function of the mouth during digestion?

mechanical digestion (chewing) + chemical digestion of starch by amylase

what is the function of the oesophagus during digestion?

muscular tube that moves food to stomach by peristalsis

what is the function of the stomach during digestion?

muscular bag that secretes gastric juices containing pepsin, breaking down proteins into peptides

what is the function of the small intestine (duodenum) during digestion?

first part, finishes chemical digestion using enzymes from pancreas

what is the function of the small intestine (ileum) during digestion?

where most nutrient absorption happens with help of villi into blood

what is the function of the large intestine (colon) during digestion?

absorbs water + minerals from remaining material

what is the function of the large intestine (rectum) during digestion?

stores faeces before egestion

what is the function of the pancreas during digestion?

produces digestive enzymes such as amylase, lipase, trypsin, which are released into duodenum to aid digestion

describe the structure of the ribs

bones that form a cage to protect lungs + heart

describe the structure of the intercostal muscles

between ribs, helps moving ribcage

describe the structure of the diaphragm

domed sheet of muscle under lungs, moves for breathing

describe the structure of the trachea

windpipe with C-shaped cartilage rings to keep the airways open

describe the structure of the bronchi

two tubes from trachea into each lung

describe the structure of the bronchioles

smaller branches inside lungs

describe the structure of the alveoli

tiny air sacs where gas exchange occurs

describe the structure of the pleural membranes

double layer around lungs with pleural fluid, form an airtight, slippery surface

what do the intercostal muscles and diaphragm do during inhalation?

• diaphragm contracts, moves down and flattens

• external intercostal muscles contract, moving ribs up and out

• thorax volume increases, pressure decreases, so air moves into lungs

what do the intercostal muscles and diaphragm do during exhalation?

• diaphragm relaxes, moves up and domes

• intercostal muscles relax, ribs move down and in

• thorax volume decreases, pressure increases, so air moves out of lungs