Cell Structures and Functions

• Animal cells' ribosomes, endoplasmic reticulum, and mitochondria are visible under an electron microscope.
• Plant cells lack certain organelles like a permanent vacuole, cell wall, and chloroplasts, and have a more regular structure than animal cells.

The Functions of Cell Parts

• Nucleus contains chromosomes, 46 in humans, carrying genetic information and controls cell activity by controlling protein synthesis.
• Cytoplasm facilitates chemical reactions.
• Cell membrane regulates substance passage in and out of the cell, selectively permeable.
• Cell wall protects the cell and provides support.
• Chloroplasts facilitate photosynthesis in plants.
• Mitochondria perform respiration reactions.
• Endoplasmic reticulum is vital for protein synthesis and transport, forming a network of membranes.
• Ribosomes on the endoplasmic reticulum assemble proteins based on mRNA instructions.
• DNA contains two strands of alternating sugar and phosphate groups in a double helix, linked by two nitrogen bases at each "rung".
• DNA includes four bases: Adenine(A), Thymine(T), Cytosine(C), and Guanine(G), with A always paired with T, and C with G.

Mitosis

• Mitosis separates a cell into two with identical sets of chromosomes, crucial for growth, repair, cloning, and asexual reproduction.
• Prophase duplicates the cell's DNA.
• Metaphase aligns centrioles with duplicated DNA along the equator, using tubules to connect to the centromere.
• Anaphase pulls half the chromosomes to opposite directions.
• Telophase closes and splits the cell membranes.

The Organisation of Cells

• Specialised cells with similar functions form tissues.
• Bones are collections of cells secreting calcium salts.
• Muscles can be voluntary, involuntary, or cardiac.
• Blood is a collection of red and white blood cells.
• Nervous tissue generates the brain, nerves, and spinal cord.
• Epithelium lines organs and can be squamous or ciliated.
• Tissues with the same function form organs, like the heart.
• Organs with the same function create organ systems, like the circulatory system.
• Organ systems form organisms, e.g., humans.

Biological Molecules

• Carbohydrates contain Carbon, Hydrogen, and Oxygen.
• Carbohydrates are grouped into polysaccharides (starch), disaccharides (sucrose), and monosaccharides (glucose).
• The test for starch involves iodine, which changes from red-orange to blue-black in starch presence.
• The test for glucose uses Benedict's Reagent; heated solutions turn from blue to brick-red with glucose.
• Proteins contain Carbon, Hydrogen, Oxygen, and sometimes Sulfur.
• Proteins consist of amino acid subunits.
• The test for protein uses a biuret solution, (Sodium Hydroxide and Copper Sulphate), changing from blue to pink-purple when protein is present.
• Lipids contain Carbon, Hydrogen, and Oxygen.
• Lipids are made of a glycerol molecule and three fatty acids.
• The test for lipids requires ethanol, turning the solution cloudy if lipids are present.
• Enzymes are biological catalysts, speeding up reactions without being altered.
• Enzymes have an active site where the substrate fits, described by the lock and key model.
• Enzymes are specific, with only one enzyme type fitting each substrate, catalyzing metabolic reactions.
• Enzyme activity increases with temperature, boosting kinetic energy and collisions between enzymes and substrates.
• Enzymes denature beyond the optimal temperature, altering the active site.
• pH also affects enzymes; the active site changes if the optimal pH is not reached.
• Experiment to show enzyme activity with temperature involves mixing amylase and starch at different temperatures and testing with iodine.

Movement of Substances

• Diffusion is the movement of particles from high to low concentration.
• Osmosis is water molecule movement from high to low water potential through a partially permeable membrane.
• Active transport moves particles against a concentration gradient using energy from respiration and carrier proteins.
• Substances move into and out of cells via diffusion, osmosis, and active transport.
• High concentration gradients, high temperatures and large surface area to volume ratios increase movement rates.
• Diffusion experiment involves observing how potassium permanganate agar jelly cubes in hydrochloric acid change over time.

Osmosis Experiment

• Pour distilled water, a 0.85% salt solution, and a 3% salt solution into the test tubes.
• Add fresh blood to each test tube.
• Check under a microscope.
• Tube one should exhibit no red blood cells because of lysis, tube two should show normal red blood cells, and tube three should show shrunken red blood cells.
• Both diffusion and osmosis experiment uses visking tubing filled with a substance, placed in beakers with varying concentrations. The amount of substance should then change.

Form and Movement

• Axial skeleton includes the skull, ribcage, and vertebral column.
• Appendicular skeleton includes the scapula, clavicle, pelvis, and limbs.

Long Bones

• Long bones include the femur and humerus
• Parts of the bone include: Articular cartilage, Epiphysis, Diaphysis, Spongy Bone, Growth Plate, Periosteum, Compact Bone
• The skeleton provides protection, shape, support, movement, and blood production.

Joints

• Joints are needed at bone meeting points for movement.
• The hinge joint, found at the elbow, prevents movement past 180° in one plane.
• The ball and socket joint, located at the shoulder and hip, allows 360° movement in three planes.
• The cartilaginous intervertebral joint in the vertebral column uses cartilage discs for movement.
• Immovable joints, present in the skull, do not allow movement.
• Synovial joints facilitate smooth bone movement with articular cartilage for friction reduction and act as shock absorbers. They contain synovial fluid for lubrication and ligaments to hold bones in place.
• Muscles induce movement; tendons pull bones when muscles contract. Muscles work in antagonistic pairs, for example biceps moving the radius up and triceps moving it down.

Muscle and Bone Growth Nutrients

• Muscles need protein and Vitamin D.
• Bones require calcium, Vitamin D, and phosphate.

Coordination: Neurons

• Neurons include: Dendrite, Cell body, Axon, Myelin sheath
• The central nervous system, contains the brain and spinal cord and issues orders to the body.
• An electrical impulse travels from a nerve receptor along the axon.
• At the synapse neurotransmitters are released and bind with receptors on the second neuron.
• This stimulates the second neuron, and unused neurotransmitters are reabsorbed or broken down.
• The spinal cord coordinates information from sensory to motor neurons via relay neurons.

Reflex Arc

• Receptor cells detect a stimulus
• An electrical impulse goes to the central nervous system (CNS)
• Travels to a relay neuron, then passes to the motor neuron.
• The impulse travels to the target muscle or effector gland, creating an effect.
• Spinal reflexes like the knee jerk and withdrawal reflex are involuntary, with information reaching the brain after the reflex.
• The brain has two cerebral hemispheres divided by a fissure: the left controls the right body side and is for language, maths, and logic. The right hemisphere handles music, visual imagery, and spatial awareness.
• The cerebellum coordinates voluntary movements, posture, balance, and speech.
• The mid-brain regulates hearing, vision, arousal, motor control and body temperature.
• The pituitary gland, located at the front of the mid-brain, secretes regulatory hormones
• The hypothalamus, above the pituitary gland, links the nervous and endocrine systems, controls homeostasis, sleep-wake cycles, and motor control.

Hormones

• Pituitary gland hormones include Anti-Diuretic Hormone (ADH) for osmoregulation and Gonadotrophin to control sperm and ovulation production.
• Adrenal glands produce Adrenaline, preparing the body for "fight or flight" by increasing heart rate, blood pressure, pupil size, and metabolism.
• The thyroid gland produces Thyroxine to control metabolic rate.
• The pancreas secretes Insulin to help control blood sugar by signalling liver, muscle, and fat cells to uptake glucose and Glucagon to convert stored glycogen into glucose.
• Hormones like pituitary growth, thyroid, and sex hormones are essential for growth and development.
• Instruction move around the body via the Nervous and Endocrine System
• Neurons use electrical impulses; hormones use chemicals.
• Neurons target specific cells, hormones target general cells.
• Hormones work slower compared to the fast effect of neurons
• Hormone effects are longer-lasting compared to the short duration of the neuron effect.

Negative Feedback

• Negative feedback mechanism is a response to conditions away from the ideal state. The skin controls temperature while ADH regulates osmoregulation.

The Eye

• Eye components include: suspensory ligaments, iris, cornea, lens, sclera, choroid, retina, fovea, optic nerve, vitrous humour
• The eye is a photorecptor
• The eye detects light changes.
• The eye transduces light energy into electrical impulses.
• Impulses are interpreted as images.
• The eye can focus and bend light and respond to light changes.
• Ciliary muscles contract for near objects, relaxing suspensory ligaments to make the lens convex and for distant objects, the ciliary muscles relax, stretching the lens thin and flat.
• The iris dilates the pupil in dim light, contracting radial muscles. In bright light, the iris shrinks the pupil.
• Stereoscopic vision is seeing a scene with both eyes differently to perceive depth and distance, essential for sports.

The Ear

• Ear Components: Semicircular canals, Stirrup, Anvil, Auditory nerve, Hammer, Pinna, Ear drum, Auditory canal, Entrance to cochlea, Round window
• Function of the ear is hearing.
• The ear's pinna directs sound waves to the ear canal, vibrating the eardrum. The ossicles transmit vibrations to the cochlea's liquid.
• Ciliary cells in the liquid amplify sounds, categorizing them by frequency. The auditory nerve transmit this information to the brain which interprets them as noises.
• Balance is regulated by semicircular canals that detect movement, sending impulses to the brain, which sends impulses, to help us know where we are.

Nutrition and Energy

• Balanced Diet: eating foods regularly with the right nutrients (carbs, lipids, protein, minerals, vitamins, water and fibre) in the right proportions.
• Diet changes based on age, pregnancy, and occupation, affecting energy needs.

Digestive Sustem

• Mouth: Food is broken down, saliva begins starch digestion.
• Esophagus: helps food move down to the stomach.
• Stomach: Food mixes with hydrochloric acid and pepsin, sterilize the food, breaking down proteins.
• Pancreas: Hydrogen carbonate neutralizes stomach acids for the enzymes.
• Small intestine: has the duodenum where food mixes bile and pancreatic juices. The ileum is also here, which helps digest the food.
• Large intestine: water and vitamins are absorbed from undigested food and faeces is stored in the rectum.

Bile

• Bile is produced in the liver, it emulsifys fats in the duodenum.

Peristalsis

• Peristalsis is muscle contractions which widen and narrow gut walls.
• This moves food along the digestive system
• Fiber is needed to help move food along

Digestive Enzymes:

• Amylase helps break down starch into maltose and its produced in the glands, pancreas and gut walls.
• Maltase helps break down maltose into glucose and is also produced in the glands, pancreas and gut walls.
• Protases help to break down proteins into peptides. It is produced in the organs, pancrease and gut walls.
• Lipase helps to break down lipids into fatty acids and the enzymes are produced in the pancreas

Features of the Vilus

• Increases surface area to volume
• Has circular shape with lots of blood
• Only one type of epithelium cell

Teath:

• Incisors cut food
• Canines grip food
• Premolars crush foods
• Molars chew and grind food

Factors effect teeth growth

• Calcium, Vitamin D, genetics, care
• Brush teeth twice a day, floss, dont eat too much suger, rinse mouth wash

Respiration

• This is used to release energy in living things, aerobic takes place with oxygen and anaerobic doesn't.

Disease

• Involves the stages; infection, incubation and signs

Gaseus exchange

• Uses the alveoil to alow gasses in and out

Lung Volumes

• Inhalation pushes the ribs ip and diaphragm down which creates more air to get into the lungs.
• Emphysema causes the amount of oxygen to lower
• Lung Cancer causes cigaretes to cause

Exercise

• Causes the heart rate to increase
• Blood diversifies
• Body improves.

The Blood

• Contains plasma, red and white blood cells

Kidney

• The kidney if it fails, you would die

Liver

• The liver breaks down drugs

Reproduction

• Male has spermduct, bladder, seminal vesicle, penish with foreskin and erectial tissue
• Female, endomitrium, utheras, fallopian tube.