Year 11 Module 2: IQ 2.1, 2.2, 2.3 Flashcards
(44 cards)
What is the difference between unicellular, multicellular and colonial organisms?
Unicellular: one cell (bacteria, amoeba)
Multicellular: Organisms made up of many specialised cells (humans, dog, monkey)
Colonial: collections of individual cells that live together in a colony, often with specialised functions, but each cell can still function independently if separated. They represent a step between unicellular and truly multicellular organisms (biofilm)
Differentiation and specialisation of cells?
Cell differentiation, also known as cell specialisation, is the process by which cells become specialised for different functions. Such as stem cells differentiating into specialised functions of B and T cells
Levels of cell organisation
Organelles –> Cells –> Tissues (collection of same cells) –> Organ –> Organ System –> Organism
What is the difference between autotrophs and heterotrophs?
Autotrophs are organisms that produce their own food (energy and nutrients) (plants, algae- photosynthesis) and heterotrophs are organisms that rely on other organisms/organic matter for their energy and nutrients (animals, fungi)
What are the three types of plant tissues and their role?
1.)Dermal tissue: forms the outer protective coating of plants organs (epidermis of root and leaf)
2.)Vascular tissue (middle): transport of material throughout the plant (xylem transports water up the plant from roots to leaves and phloem translocates sugars)
3.)Ground tissue: makes up the remainder of the plant, found between dermal and vascular tissue (stores water and nutrients)
Explain gas- exchange in plants
Gas exchange in plants occurs mainly in the leaves, specifically through stomata (tiny pores on the underside of the leaf). Inside the leaf, spongy mesophyll cells provide a moist surface and air spaces to facilitate the diffusion of gases. Carbon dioxide enters for photosynthesis, while oxygen (from photosynthesis) and carbon dioxide (from cellular respiration) are exchanged with the atmosphere. The large surface area of leaves and the internal structure maximise the efficiency of this gas exchange.
Explain gas- exchange in humans
Gas exchange in humans happens in the alveoli of the lungs. Oxygen is breathed into trachea, through bronchiole tubes, bronchioles and into alveoli. The alveoli have a high SA with aqueous environment for diffusion of oxygen.
Oxygen from inhaled air diffuses into the capillaries, while carbon dioxide diffuses from the blood into the alveoli to be exhaled.
Gas exchange in humans is a passive process meaning it is going with the concentration gradient
Explain gas- exchange in insects
Insects use a system of tracheae and tracheoles to exchange gases directly with their body cells.
Air enters through spiracles (tiny holes) and travels through the tracheal tubes.
Oxygen diffuses directly into cells; no blood is involved.
The large surface area of tracheoles and their closeness to cells make gas exchange efficient.
Explain gas- exchange in fish
Fish use gills for gas exchange.
Water enters through the mouth and passes over the gill filaments, which contain many lamellae to increase surface area.
Oxygen diffuses from water into the blood in the gills, while carbon dioxide diffuses out into the water.
A counter-current flow between water and blood maximises oxygen absorption.
What are the two modes that account for transport in plants? And what do they transport?
1.)Pressure-flow theory (sugar moved up and down/translocated through phloem)
2.)Adhesion-cohesion theory (water moved up from roots to leaves through xylem)
Explain the pressure flow theory
Sugars produced in the leaves (source) are actively transported into the phloem sieve tubes. This active transport requires energy because sugars move from areas of low concentration to high concentration inside the phloem.
The high concentration of sugar in the phloem causes water to enter from the xylem by osmosis, creating a high osmotic pressure in that area.
This pressure causes the sugary sap to flow through the phloem from the source (where sugar is loaded) to the sink (where sugar is used or stored, like roots or fruits).
At the sink, sugars are actively transported out of the phloem, lowering the osmotic pressure there, and water exits back to the xylem, maintaining a pressure gradient that drives the flow.
Explain adhesion-cohesion theory
Water moves up the xylem from roots to leaves through a process driven by negative pressure (tension) created by transpiration at the leaves. When water evaporates from the leaf surface, it creates a suction force that pulls water upward.
Cohesion is the attraction between water molecules, helping them stick together in a continuous column inside the xylem. Adhesion is the attraction between water molecules and the walls of the xylem vessels, helping the water column resist gravity.
This movement is not active transport because it doesn’t use energy from the plant — instead, it relies on physical forces (negative pressure) generated by transpiration. The negative pressure pulls water upward through the plant, from roots to leaves, maintaining a steady flow.
What is active and passive transport?
Active transport is the movement of molecules across a cell membrane using energy (ATP), usually moving substances from low to high concentration against their concentration gradient.
Passive transport is the movement of molecules across a membrane without using energy, moving substances from high to low concentration down their concentration gradient. Examples include diffusion and osmosis.
What is diffusion and what is osmosis?
Diffusion is the movement of particles from an area of high concentration to low concentration until they are evenly spread out.
Osmosis is the diffusion of water molecules through a semi-permeable membrane from an area of low solute concentration to high solute concentration to balance solute levels.
Explain the process of digestion in the mammalian digestive system?
1.) Mouth (saliva glands in mouth produce amalayse enzyme to help break down food)
2.)Teeth (breaks down food mechanically and forms chyme)
3.)Epiglottis (closes over trachea)
4.)Oesophagus (muscular tube that connects mouth to stomach to move bolus)
5.)Stomach (uses mechanical digestion to churn food, produces pepsin enzyme and HCI acid to kill bacteria and give the right pH for pepsin to work)
6.)Pancreas (produces protease-to digest proteins, amalayse-digests carbs and lipase-digests down fat enzymes and releases these into the small intestines)
7.)Small intestine (where absorption occurs through the high SA of villi and microvilli, nutrients are absorbed out of the alimentary canal into the body)
8.)Large intestine (primarily absorbs water and electrolytes, converts undigested material into solid waste)
9.)Anus (excretes feces)
What is the main function of the digestive system?
To break down nutrients into molecules small enough to be able to pass through cell membranes into cells for the use in the production of energy and metabolism
4 main sections of digestion?
Ingestion: This is the process of taking food into the mouth. It involves chewing (mechanical digestion) which breaks food into smaller pieces, and mixing it with saliva which contains enzymes to begin chemical digestion.
Digestion: Food is further broken down both mechanically (like churning in the stomach) and chemically (enzymes breaking down carbohydrates, proteins, and fats into smaller molecules).
Absorption: The small molecules resulting from digestion (like glucose, amino acids, and fatty acids) are absorbed primarily in the small intestine. They pass through the intestinal walls into the bloodstream or lymph to be transported to cells.
Egestion (Elimination): Undigested and unabsorbed food, along with waste products, move into the large intestine where water is absorbed, and the remaining material is formed into feces and eliminated through the anus.
What does digestive systems of herbivores have and why?
Because herbivores take carbs from cellulose of plant cell walls, it is hard to break down and therefore they have more than one stomach; foregut or hindgut where fermentation takes place through the help of enzymes (symbiotic relationship)
Nutrient and gas requirements of autotrophs?
Autotrophs (e.g., plants):
Carbon dioxide (CO₂): Absorbed from the air and used in photosynthesis to produce glucose.
Oxygen (O₂): Released during photosynthesis; also taken in for cellular respiration to break down glucose for energy.
Glucose: Produced internally via photosynthesis; used as an energy source and to build other organic molecules.
Water (H₂O): Absorbed from the soil; essential for photosynthesis and metabolic activities.
Proteins: Synthesized using nitrogen and mineral ions from the soil, combined with carbon from glucose.
Mineral ions: Such as nitrogen, phosphorus, potassium, and magnesium, absorbed from soil; important for enzyme function and growth.
Nutrient and gas requirements of heterotrophs?
Carbon dioxide (CO₂): Produced as a waste product during cellular respiration and expelled.
Oxygen (O₂): Taken in from the environment for cellular respiration to break down glucose and release energy.
Glucose: Obtained by consuming plants or other organisms; primary energy source.
Water (H₂O): Obtained from food and drink; vital for biochemical reactions and bodily functions.
Proteins: Obtained from diet, broken down into amino acids used for growth, repair, and enzyme production.
Mineral ions: Obtained from food; essential for various physiological functions like nerve signaling and bone health.
What are the components of blood?
Red blood cells (45%), white blood cells (1%), plasma (54%) platelets
Function of the heart?
The heart is a muscular organ that pumps blood throughout the body
Function of atrium?
The function of the atrium is to receive blood returning to the heart and then pump it into the ventricle for further circulation. The right atrium receives deoxygenated blood from the body, while the left atrium receives oxygenated blood from the lungs.
Function of ventricles?
The function of the ventricles is to pump blood out of the heart to the lungs or the rest of the body. The right ventricle pumps deoxygenated blood to the lungs for oxygenation, while the left ventricle pumps oxygenated blood to the entire body.
