Biology FULL Preliminary 2020 PDF

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BIOLOGY PRELIMINARY NOTES MODULE 1: CELLS AS THE BASIS OF LIFE Outcomes -

Conducts investigations to collect valid and reliable primary and secondary data information Selects and processes appropriate qualitative and quantitative data and information using a range of appropriate media Describes single cells as the basis for all life by analysing and explaining cells ultrastructure and biochemical processes

Content Focus Cells are the basis of life. They coordinate activities to form colonial and multicellular organisms. Students examine the structure and function of organisms at both the cellular and tissue levels in order to describe how they facilitate the efficient provision and removal of materials to and from all cells in organisms. They are introduced to and investigate biochemical processes through the application of working scientifically skills processes. These tools will be used throughout the course to assist in making predictions and solving problems of a multidisciplinary nature.

Content Cell Structure Inquiry Question: What distinguishes one cell from another? ● Investigate different cellular structures, including but not limited to; ○ Examining a variety of prokaryotic and eukaryotic cells Prokaryote -

No membrane-bound organelles - No nucleus - Commonly unicellular - 0.1 - 5.0 micrometres - DNA is single, circular chromosome - May contain plasmids Examples: - Bacteria - Archaea

Similarities -

Cell membrane Cytoplasm DNA Ribosomes - Protein synthesis

Differences between plant and animal cells: - Plant cells

Eukaryote -

Includes membranebound organelles - Includes nucleus - Each organelle has a set function - Can be multi or unicellular - DNA is arranged in linear chromosomes - Located in nucleus Examples: - Protista - Fungi - Plants - Animals

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Tough cell wall on the outside of their membrane Many plant cells have a large vacuole Many plant cells contain chloroplasts - Note: not ALL plant cells have a chloroplast - Example; cells in the underground roots cannot

photosynthesise, so do not contain any chloroplasts ○ Describe a range of technologies used to determine a cell’s structure and function Light microscope: Energy Source

Light

Specimen

Thin or whole organism (dead or alive)

Treatment

Stains can be applied to highlight different components of the cell

Image

Can display inside the cell or the whole organism

Transmission electron microscope: Energy Source

Electrons

Specimen

Ultra-thin section or whole microscopic dead organism

Treatment

Stained, dehydrated, fixed specimen embedded in resin and sectioned

Process

Electrons transmitted through the specimen

Image

Can display inside the cell or whole organism, multiple images can create a 3D image

Electron microscope: - Highly detailed

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Higher resolution Produces black and white images

Scanning electron microscope: Energy Source

Electrons

Specimen

Thin section or whole organism (dead or alive)

Treatment

Stained, dehydrated, fixed specimen, coated in a thin layer of metal atoms

Process

Bombard specimen with electrons and rebound pattern

Image

3D surface view

● Investigate a variety of prokaryotic and eukaryotic cell structures, including but not limited to; ○ Drawing scaled diagrams of a variety of cells Estimating cell size: Cell size =

Diameter of field of view No . of cells across field of view

○ Comparing and contrasting different cell organelles and arrangements Cell structure and function: Organelles: - In the cytoplasm - Visible using a microscope - Each organelle has a specific function Cytoplasm: - A watery, gel-like substance - Place where chemical reactions, food storage and other “cellular activity” takes place

Nucleus: - The most important part of the cell - Control centre - Long strands of DNA are stored here - Explains how the cell should act - When the cell makes a new cell it copies the DNA found here Vacuoles: - Storage bubbles - Found in plant and animal cells - May store food or nutrients for the cell Mitochondria: - The powerhouse of the cell which releases energy from food Endoplasmic reticulum: - Forms a pathway to allow materials to move through the cell Ribosomes: - Produces proteins for growth and repair - Found in animal cells Chloroplasts: - Converts sunlight into food - Only found in plants - Contains green chlorophyll Golgi Apparatus: - Packs chemicals into small membrane vesicles for storage or secretion - Example of this is the lysosome - Lysosomes: Garbage disposal units which remove waste

○ Modelling the structure and function of the fluid mosaic model of the cell membrane Fluid mosaic structure: - Selectively permeable membrane - Can allow some substances to move into the cell while preventing others from entering

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These membranes are dynamic structures that can form, change and reform They are made from 2 thin sheets of phospholipid bilayer sandwiched together and contain many types of embedded molecules throughout its structure

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Phospholipid bilayers: - Most important aspect of this layer is the structure of the individual phospholipid - Made of; - 1 Phosphate based head - Polar - Water-soluble - Water-loving (hydrophilic) - 2 Fat-soluble tails - Water-hating (hydrophobic) - Tails always try to avoid water

Cell Function Inquiry Question: How do cells coordinate activities within their internal environment and their external environment? ● Investigate the way in which materials can move into and out of cells, including but not limited to; ○ Conducting a practical investigation modelling diffusion and osmosis Diffusion: - Passive movement of ANY particles in a solution from areas of high to a low

concentration until equilibrium is reached - Passive as molecules are moving along the concentration gradient - Example; food dye in water

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Factors affecting the rate of diffusion: - Concentration → greater difference in concentration = faster diffusion -

Temperature → higher temp = faster diffusion occurs

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Particle size → smaller particles = faster rate

Facilitated diffusion: - Some larger particles do not readily pass through the phospholipid bilayer - They require protein channels and carrier proteins to assist them Osmosis: - “Special type of diffusion” - Occurs when the concentration gradient involves dissolved molecules or ions which CANNOT get through the membrane - Refers to the net movement of water molecules across the semipermeable membrane

Practical: Diffusion and Osmosis Aim → to observe and describe an example of diffusion and osmosis using a

selectively permeable membrane OBSERVATIONS STARCH in dialysis tubing -

Clear starch in tubing turned into a muggy, purple colour Colour suggests that yellow iodine from the water moved through the tubing and reacted with the starch

GLUCOSE in dialysis tubing -

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The initial appearance of the tubing was clear, therefore meaning there was no obvious change Once the water mixed with solution and was heating, it turned a solid orange colour suggesting the glucose had moved from the tubing to the outside

Part A: Diffusion Using 20ml of starch solution, pour into dialysis tubing and note weight and colour, place this tubing in a 200ml beaker of water and enough iodine that the water turns yellow. Leave for 20 minutes. Part B: Osmosis Using 20ml of 10% glucose solution, pour into dialysis tubing and note weight and colour, place the tubing into water and leave for 20 minutes. Collect 5ml of the water from the beaker and place into a test tube with 2ml of Benedict’s reagent added. Heat and note colour changes. (NOTE: Benedict's turns from Blue to Orange in the presence of glucose) ○ Examining the roles of active transport, endocytosis and exocytosis Passive and active transport: - Diffusion and osmosis happen automatically and not with the cell -

having to use any energy → this is a passive transport process Many other proteins, carbohydrates and other molecules regularly move in and out of cells - Cells have to deliberately move substances across the membrane using ways other than diffusion and osmosis -

These ways require the cell to use the energy (ATP from cellular respiration) to move substances → this is an active transport process Active transport process: Sodium-Potassium Pump

Endocytosis:

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Membrane pinching outwards to surround the desired substance and envelop it Membrane rejoins itself to seal the cell, leaving the targeted substance inside - Phagocytosis: (phago = eating, cyto = cell) - Cell engulf a solid material to form a food vacuole - Pinocytosis: (pino = drink) - Cell membrane engulfs liquid that contains dissolved molecules - Receptor-mediated endocytosis: - Engulfs specific substances

Exocytosis - Specialised cells need to remove wastes to distribute them to other parts of the organism - Exocytosis is the process by which cells are transported to the external environment of the cell - Membrane-bound vesicle moves to the cell membrane, fuses with it and then releases its contents to the exterior of the cell

○ Relating to the exchange of materials across membranes to the surface-areato-volume ratio, concentration gradients and characteristics of the materials being exchanged SA: V ratio: - The surface-area-to-volume ratio gets smaller as the cell gets larger

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If the cell grows past a certain point, not enough material will be able to cross the membrane fast enough - The amount of food, oxygen and other substances a cell needs depends on its volume SA divided by the V SA → Total area of the cell membrane V → space taken up by the total contents of the cell Concentration gradients: - The relative concentration of the substance on either side of the membrane affects the rate of diffusion of that substance - If the concentration gradient is high, then the substance will diffuse rapidly - In order to maintain a rapid rate of diffusion, cells need to maintain a high concentration gradient - As the concentration gradient decreases, the rate of diffusion will be slower - Once the concentration reaches equilibrium, there will be no net movement across the cell membrane

● Investigate cell requirements, including but not limited to: Cell requirements: - All organisms need to; - Take in nutrients and water - Exchange gases - Obtain energy - Remove waste - Have suitable forms of energy, including light and chemical energy in complex molecules ○ Suitable forms of energy, including light energy and chemical energy in complex molecules Energy (ATP): - All cells use glucose as the main source of energy - When glucose is broken down, it’s energy is released - It is trapped and stored in high energy molecules called adenosine

triphosphate ○ Matter, including gases, simple nutrients and ions Inorganic compounds: - Compounds without carbon atoms or simple molecules with only 1 or 2 carbon atoms - Water: makes up 70-90% of most organisms - Oxygen: required for cellular respiration - Carbon Dioxide: required for photosynthesis -

Nitrogen: key atom for 20 types of amino acids → proteins Minerals: important for building enzymes and vitamins

Organic Compounds: - Complex chemicals: containing carbon and hydrogen atoms which are found in living things: - Carbohydrates: important energy source - Lipids: important role in the cell membrane - Proteins: composed of amino acids - Nucleic Acid: composed of nucleotides - Carry genetic information ○ Removal of wastes Waste removal: - Metabolism produces products that the organism no longer requires - These MUST be removed - Excretion is the removal of any waste from an organism - Accumulation of these waste products can prevent the normal functioning of cells the cell membrane regulates the exit of waste products depending on size and concentration Waste removal from autotrophs: - Plants remove waste through their leaves - Plants produce no true waste - Aquatic plants release waste into the water Waste removal from heterotrophs: - Carbon dioxide - Nitrogenous waste - Urea in urine ● Investigate the biochemical processes of photosynthesis, cell respiration and the removal of cellular products and wastes in eukaryotic cells Photosynthesis: - The process by which plants utilise energy, typically from the sun, which is trapped by

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chlorophyll It uses this energy to break apart water and carbon dioxide molecules, build them up to oxygen, energy-storing glucose molecules and water molecules

Cellular Respiration: - All organisms break down glucose as a form of energy - Glucose can be broken down either in the; - Presence of oxygen (aerobic cellular respiration) - Absence of oxygen (anaerobic cellular respiration)

● Conduct a practical investigation to model the action of enzymes in cells Enzyme notes: - All organisms are adapted to a characteristic temperature range - This temp range allows the organism’s enzymes to control its metabolism by operating at their optimum efficiency within this range - High temperatures → (80-100°C) → Thermophiles -

Extremely low temperatures → (0-4°C) → Psychrophiles

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Most mammals → (30-45°C) - Most average around 37°C

Enzymes are biological catalysts. This means they lower the energy required to start a chemical reaction within a cell but do not get used up by the reaction.

Factors affecting enzymes: - Temperature - pH - Substrate concentration Mechanism of Enzyme actions: - Lock-and-Key Model

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On the surface of the enzyme molecule is the “active site” According to the Lock-and-Key Model, the shape of an enzyme’s active site is a perfect fit for the substrate

Induced Fit Model - A modified version of the Lock-and-Key Model - According to the Induced Fit Model, the active site is somewhat flexible and can change its shape in order to bond with the substrate

Practicals on Enzyme Activity: 1. Temperature: Clotting of milk by rennin

2. Substrate concentration: Hydrogen peroxide concentration

3. pH

● Investigate the effects of the environment on enzyme activity through the collection of primary or secondary data - Body temperature and pH are critical to survival because the vital enzymes can only perform efficiently in a narrow range of temperature and/or pH

BIOLOGY PRELIMINARY NOTES MODULE 2: ORGANISATION OF LIVING THINGS Outcomes -

Selects and processes appropriate qualitative and quantitative data and information using a range of appropriate media Solves scientific problems using primary and secondary data, critical thinking skills and scientific processes Communicates scientific understanding using suitable language and terminology for a

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specific audience or purpose Explains the structure and function of multicellular organisms and describes how the coordinated activities of the cells, tissues and organs contribute to macroscopic processes in organisms

Content Focus Multicellular organisms typically consist of a number of interdependent transport systems that range in complexity and allow the organism to exchange nutrients, gases and wastes between the internal and external environments. Students examine the relationship between these transport systems and compare nutrient and gas requirements. Models of transport systems and structures have been developed over time, based on evidence gathered from a variety of disciplines. The interrelatedness of these transport systems is crucial in maintaining health and in solving problems related to sustainability in agriculture and ecology.

Content Organisation of Cells Inquiry Question: How are cells arranged in a multicellular organism? ● Compare the differences between unicellular, colonial and multicellular organisms by: ○ Investigating structures at the level of the cell and organelle Prac investigation: Comparing different types of cells - Unicellular, colonial and multicellular organisms differ in their cell size, cell functions and cell specialisation Page 9 of Module 2 Notes Name of Specimen

Type of Cell

Estimated Size

Notes

Spermatogenesis in mammalian testes

Multicellular animal cell

Amoeba

Unicellular eukaryote

Pink stain

Volvox

Colonial organism

Different stains

Spirogyra

Plant cell

Unique shape

Unicellular Algae and Fungi

Colonial Parasites

Multicellular Birds and Humans

Cellular features

Single-cell

Many cells

Many cells

Cellular classifications

Mostly prokaryotes and some eukaryotes

Eukaryotes

Eukaryotes

One cell carries out

Individual animals,

Cells are specialised

Prokaryote OR Eukaryote

Cellular structure

all the functions to sustain life

Eg. zooids work together to sustain the colony

to perform specific functions by the organism

Functions are carried out with the cell

Functions are carried out by individuals with specific roles in the colony

Functions are carried out at cellular, tissue, organ and system level

Microscopic & Macroscopic

Microscopic - SA:V limits the size of the cell

Usually macroscopic

Macroscopic Increasing the number of cells allows for an increase in body size

Life Span

Short lifespan: - Due to the high energy output

Long lifespan

Asexual or Sexual

Mostly asexual: - Budding - Mitosis - Reproduction

Mostly asexual mitosis - Colonial reproduction

Mostly sexual

Reproductive success

The whole organism is involved

Usually, specific zooids are responsible for reproduction

Only cells specialised for reproduction (gametes) will reproduce

Cellular function -

Obtaining nutrients Exchanging gases Removing wastes

Long lifespan

○ Relating the structure of cells and cell specialisation to function Structural organisation of multicellular organisms: Organelles - Membrane-bound compartment or structure in a cell that performs a special function - Example: Mitochondria, vacuole Specialised cells - Cells that have a specific function - Example: Root hair cell, lead guard cell Tissues - A group of similar cells working together to carry out a specific function in multicellular organisms

- Example: Muscle tissue, root tissue Organs - Two or more tissues that work together to perform one or more specialised tasks - Example: Heart, liver, kidneys, flowers, leaves Systems - A group of organs that work together to perform a vital task Cell specialisation and differentiation: - Specialisation: a specialised function for a cell - Differentiation: the process where a cell changes from one type to another, typically an unspecialised cell becoming specialised Structure relating to function: Cell Red blood cells

Structure related to function -

Carry oxygen around the body Thin outer membrane allows oxygen to diffuse easily Shape increases SA: V which allows oxygen to be absorbed...