BIO GRIND

These QA flashcards cover key concepts from the lecture notes across cells, diffusion, biomolecules, digestion, respiration, excretion, homeostasis, nervous and sensory systems, infectious diseases, reproduction, genetics, ecology, plant transport, and molecular genetics.

What is the function of the nucleus in a cell?

It contains DNA (as chromatin) and controls cellular activities.

What does the nuclear envelope do?

Separates the nucleus from the cytoplasm.

What is the rough endoplasmic reticulum (RER) responsible for?

ribosomes are attached to RER and synthesises proteins for transport out of the cell.

What is the function of the smooth endoplasmic reticulum (SER)?

Synthesises fats and steroids and carries out detoxification.

What is the cytoplasm’s role in the cell?

Site where most cellular activities occur and contain organelles. (jelly-like substance for easy movement within the cell)

How do plant and animal vacuoles differ?

Plants have a large central vacuole storing cell sap; animals have several small, temporary vacuoles.

What does the Golgi apparatus do?

Modifies, sorts and packages substances into vesicles for secretion out of the cell.

Where does aerobic respiration occur and what is its outcome?

In mitochondria, it releases energy thru aerobic respiration by breaking down/oxidising glucose. (active transport)

What is the site of photosynthesis?

Chloroplasts (plants only).

Describe the cell membrane’s permeability.

Partially permeable; controls movement of substances into and out of the cell.

What is a plant cell’s cell wall made of and its permeability?

Made of cellulose; fully permeable and provides shape and structure for plant cells (mostly).

What is the role of ribosomes?

Protein synthesis.

How is a Red Blood Cell adapted for oxygen transport?

Biconcave shape increases surface area to volume ratio; lacks a nucleus to make space for to transport more oxygen that binds to more haemoglobin at one time; flexible to squeeze through capillaries as they are thin.

What features does a Root Hair Cell have to increase absorption?

Long, narrow protrusion (root hair) to increase SA:V; many mitochondria (more energy needed for ATP therefore more mito to release more energy); large central vacuole; (extra: thin cell wall to enhance nutrient uptake.)

How is a Muscle Cell adapted for contraction?

Elongated shape with many mitochondria and multiple nuclei for high energy production.

Define diffusion.

Net movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient. (does not need a permeable membrane) This process occurs until equilibrium is reached.

Define osmosis.

Net movement of water molecules from higher water potential to lower water potential through a partially permeable membrane, down a water potential gradient. This process occurs until equilibrium is reached.

Define active transport.

Movement of particles using energy, from region of lower concentration to higher concentration, through a partially permeable membrane, against a concentration gradient. (This mechanism is essential for maintaining cellular functions such as nutrient absorption and ion regulation. )

What is meant by a partially permeable membrane?

A membrane that allows certain substances to cross but not others.

How does the biconcave shape of RBCs aid diffusion?

Increases surface area to volume ratio for faster oxygen diffusion, shorter diffusion distance.

What is the linking structure-to-function concept in cells like RBCs, root hair cells, and muscle cells?

Structure (e.g., shape, organelles) determines function (e.g., diffusion rate, transport, energy production).

What are the three main biomolecule test types covered in the notes and what do they detect?

Iodine test for starch; Benedict's test for reducing sugars; Biuret test for proteins; Ethanol emulsion test for fats.

What are the basic elements and monomer units of carbohydrates, fats, and proteins?

Carbohydrates: C, H, O; Monosaccharides (e.g., glucose). Fats: glycerol + fatty acids. Proteins: amino acids.

What is the function of starch, glycogen, and cellulose in biomolecules?

Starch and glycogen store glucose energy; cellulose provides structural support in plants.

What is the Lock and Key model in enzyme action?

A specific substrate fits an enzyme’s active site like a key fits a lock, forming an enzyme-substrate complex and lowering activation energy.

What environmental factors affect enzyme activity?

Temperature and pH affect enzyme shape and activity; optimal values yield maximum rate.

What are the general benefits of enzymes?

They speed up reactions, work at lower temperatures, remain chemically unchanged, and are highly specific.

What are the main parts of the alimentary canal and their processes?

Mouth: ingestion and digestion; Stomach: digestion with gastric juice; Small intestine: digestion, absorption, assimilation; Large intestine: absorption of water; Anus: egestion.

What is the role of the duodenum, jejunum, and ileum in digestion and absorption?

Duodenum: digestion; Jejunum: digestion and absorption; Ileum: absorption mainly.

What does bile do in fat digestion?

Bile salts emulsify fats into smaller droplets, increasing the surface area for lipase.

Which enzymes are produced by the pancreas and where are they active?

Pancreatic lipase (fats), pancreatic amylase (starch), and protease; active in the small intestine.

What are villi and what makes them efficient for absorption?

Finger-like projections in the small intestine; one-cell-thick epithelium, microvilli, and rich blood supply to maintain diffusion gradients.

What is the function of the liver in digestion and metabolism?

Detoxification, hormone breakdown, bile production, deamination of amino acids, glucose regulation.

What is peristalsis and why is it important?

Rhythmic, wave-like muscular contractions that move food along and mix it with digestive juices.

Describe the adaptations of the alveoli for gas exchange.

One-cell-thick walls, many capillaries, large SA:V, and a thin moisture film to dissolve gases for diffusion.

What are inspired vs. expired air differences?

Inhaled air has higher O2 and lower CO2 than exhaled air; exhaled air is richer in CO2 and water vapour.

Name common harmful effects of tobacco smoke.

Nicotine (addiction, increases BP and clotting), carbon monoxide (reduces O2 transport), tar (carcinogen; damages cilia).

Where does respiration occur in the cell and what are the two types?

Mitochondria for aerobic respiration; Cytoplasm for anaerobic respiration (lactic acid in humans, ethanol in yeasts).

What is the pathway of air into the lungs during inspiration and out during expiration?

Inspiration: diaphragm contracts, intercostal muscles contract, thoracic volume increases, air drawn in. Expiration: diaphragm relaxes, intercostal muscles relax, thoracic volume decreases, air forced out.

What is the composition and function of blood plasma and cells?

Plasma (55%): carries dissolved substances; Red blood cells: carry O2 via haemoglobin; White blood cells: fight infection; Platelets: clotting.

How do red blood cells become biconcave, and why is this beneficial?

Biconcave shape increases surface area for gas exchange and enables flexible movement through capillaries.

What are the roles of white blood cells?

Phagocytes engulf pathogens; Lymphocytes produce antibodies for targeted immune response.

What is the function of platelets?

Promote blood clotting at injury sites to prevent blood loss and infection.

What are antibodies and their role in immunity?

Proteins produced by lymphocytes that clump pathogens (agglutination), neutralise toxins, and promote phagocytosis.

What are the universal blood group concepts AB and O?

AB is the universal recipient; O is the universal donor; only RBCs are transfused.

Describe arteries, capillaries, and veins in terms of structure and function.

Arteries: carry blood away from the heart; thick walls; high pressure. Capillaries: one-cell-thick walls; high surface area; site of exchange. Veins: carry blood to the heart; valves; lower pressure.

What is the cardiac cycle and the order of valve movement in a heartbeat?

AV valves close; SL valves open at systole; SL valves close and AV valves open at diastole; generates lub-dub sounds.

What causes a heart attack and how can it be prevented?

Blockage of a coronary artery due to atherosclerosis; prevent with diet, no smoking, exercise, and stress management.

What are the two main gas exchange processes in the respiratory system?

Gas exchange between alveoli and blood; transport of O2 and CO2 in the bloodstream.

What is osmoregulation and the role of ADH?

Regulation of water balance; ADH increases water reabsorption in collecting ducts to maintain blood water potential.

What is the structure and function of the kidney and nephron?

Kidneys filter blood; nephrons perform ultrafiltration and selective reabsorption to form urine.

What is dialysis and how does a dialysis machine work?

A process to filter waste from blood when kidneys fail; uses a semi-permeable tube and dialysate in opposite flow to maintain diffusion gradients.

Name key components of the eye and their roles.

Sclera: protects; Choroid: blood supply; Retina: contains photoreceptors; Cornea: refraction; Iris: controls pupil size; Lens: focuses; Ciliary body: adjusts lens; Aqueous humour and Vitreous humour maintain shape and refract light.

What is accommodation in the eye?

Adjusting the lens shape via ciliary muscles and suspensory ligaments to focus on near or far objects.

Describe the pupil reflex in terms of radial and circular muscles.

Radial muscles dilate the pupil in low light; circular muscles constrict the pupil in bright light to reduce light entry.

What is the difference between reflex actions and voluntary actions?

Reflex actions are automatic, rapid, and involve a reflex arc; voluntary actions are deliberate and controlled by the brain.

What is the reflex arc sequence from stimulus to response?

Stimulus → Receptor → Sensory neuron → Relay neuron (in CNS) → Motor neuron → Effector → Response.

Define infection vs non-infection diseases and give examples.

Infectious diseases are caused by pathogens (e.g., cholera, influenza) and spread by droplets, contact, etc.; non-infectious diseases (e.g., atherosclerosis, diabetes) do not spread.

How do bacteria differ from viruses in terms of structure and treatment?

Bacteria have cell walls, membranes, metabolism and can be killed by antibiotics; viruses have no cellular structure and are not killed by antibiotics.

What is a vaccine and how does it protect you?

A preparation containing antigens that stimulate white blood cells to produce antibodies; long-lasting immunity may persist.

What is meiosis and why is it important?

Meiosis produces four genetically different haploid cells; ensures genetic variation and halving of chromosome number for sexual reproduction.

What is the difference between mitosis and meiosis?

Mitosis produces identical diploid cells; meiosis produces four genetically diverse haploid cells.

What is a mono-hybrid cross?

A cross examining one trait with two alleles to predict offspring ratios.

What is a dominant vs recessive allele?

Dominant allele expresses itself in homozygous or heterozygous form; recessive only expresses when homozygous recessive.

What is the concept of sex determination described in the notes?

Sex is determined by sex chromosomes: XX is female, XY is male; paternal X or Y determines offspring sex.

What is a mutation and give an example linked to disease?

A sudden change in DNA sequence; e.g., sickle-cell anemia from a single-base substitution in the haemoglobin gene.

What is natural selection and what conditions drive it?

Traits offering a selective advantage increase survival and reproduction; variation and environmental pressures drive selection.

Explain continuous vs discontinuous variation.

Discontinuous: few distinct phenotypes (e.g., blood type). Continuous: a range of phenotypes (e.g., height) influenced by multiple genes.

What is a carbon sink and give examples?

An area that stores carbon long-term (e.g., forests, oceans) and releases less carbon than it takes in.

What is biomagnification?

Toxic substances increase in concentration higher up the food chain through repeated consumption.

Why is photosynthesis essential and what is the general equation?

Converts CO2 and water into glucose and oxygen using light energy; glucose used for energy and growth.

What are key factors affecting photosynthesis?

Light intensity, CO2 concentration, and temperature; each can limit the rate of photosynthesis if insufficient.

What is transpiration and what factors affect it?

Loss of water vapour from plant leaves via stomata; affected by temperature, light, humidity, and wind.

What is transpiration pull?

The suction force created by transpiration that helps draw water up the xylem from roots to leaves.

What is the function of xylem and phloem?

Xylem transports water and mineral salts; phloem translocates manufactured food (sap) from leaves to other parts.

What is a plant’s wilting and its causes?

Wilting occurs when transpiration exceeds water uptake, leading to loss of turgor pressure in cells.

What are adaptations to reduce transpiration in plants?

Hairs, sunken stomata, rolled leaves, thick cuticle, succulent leaves to store water.

What is the difference between a carbon cycle and a carbon sink?

The carbon cycle describes carbon movement through organisms and the environment; carbon sinks store carbon long-term.

What is the role of DNA in genetics?

DNA carries genetic information; it codes for proteins via transcription and translation.

What is a plasmid and how is it used in genetic engineering?

A small circular DNA molecule used as a vector to carry foreign genes into bacteria.

What are restriction enzymes and sticky ends?

Enzymes that cut DNA at specific sequences; sticky ends have overhangs that facilitate ligation of genes into plasmids.

What is a recombinant plasmid?

A plasmid that carries a foreign gene inserted via ligation of sticky ends.

What is the general process of genetic engineering to produce human insulin?

Cut human gene and plasmid with restriction enzymes, join fragments with DNA ligase, insert recombinant plasmid into bacteria, and select for bacteria that produce insulin.

What are asthat are the main carriers in blood plasma?

Blood plasma carries glucose, amino acids, minerals, hormones and wastes; RBCs, WBCs, and platelets are separate components.

What is osmoregulation’s negative feedback control involving ADH?

Osmoreceptors detect changes in water potential; ADH secretion adjusts collecting duct permeability to water to restore set-point.

What is the process of fertilisation in flowers?

Pollen tube grows, releases male nucleus that fuses with ovum forming a diploid zygote; endosperm also formed from other nuclei.

What does the placenta do in pregnancy?

Transfers nutrients and oxygen to the fetus; removes waste; secretes hormones to maintain pregnancy.

What is the role of amniotic fluid?

Cushions and protects the fetus, allows movement, maintains temperature, and helps with development.

Explain the difference between a gene, allele, chromosome, and chromatin.

Gene: a sequence coding for a polypeptide; allele: variant form of a gene; chromosome: long DNA with many genes; chromatin: loosely packed DNA in the nucleus.

What is a memory shortcut to remember the stages of menstrual cycle hormones?

Menses: oestrogen dominates; Fertile period: ovulation around day 14 with rising oestrogen; Luteal phase: progesterone dominates for maintenance.

What is a disease resistance concept behind antibiotic resistance?

Bacteria variants may survive antibiotics; surviving bacteria reproduce, leading to resistant strains; incomplete courses worsen it.

What is the difference between a universal donor and universal recipient in blood transfusion?

O is the universal donor; AB is the universal recipient; only RBCs are transfused to avoid antibodies.

What is the role of the heart’s chordae tendineae and the septa?

Chordae prevent valve inversion; the septum separates the left and right sides to keep oxygenated and deoxygenated blood separate.

What is the function of the cornea and lens in vision?

Cornea refracts most light; lens fine-tunes focus onto the retina through accommodation.

What changes occur in the iris during pupil reflex in bright vs dim light?

In bright light, circular muscles contract to constrict pupil; in dim light, radial muscles contract to dilate pupil.

How does the liver detoxify harmful substances?

Converts toxins to harmless forms and processes drugs for elimination.

What is peristalsis’s antagonistic muscle action?

Circular and longitudinal muscles contract and relax in alternation to move content along the gut.

What is a fat emulsion’s significance in digestion?

Emulsification increases fat surface area for lipase to act, aiding fat digestion.

What is a catalyst in biology?

A substance that speeds up a chemical reaction without being consumed; enzymes are biological catalysts.