Animal, Plant, and Bacteria Cells

Structures in Animal Cells

• The cell membrane controls the entry and exit of substances.
• The cytoplasm is the location of chemical reactions.
• The nucleus contains chromosomes made of DNA.
• The nuclear membrane surrounds the nucleus.
• Mitochondria are the sites of respiration.

Structures in Plant Cells

• Plant cells share features with animal cells.
• The cellulose cell wall maintains cell shape and structure.
• Vacuoles contain cell sap and provide support by pushing the cell membrane against the cell wall.
• Chloroplasts are where photosynthesis occurs and contain chlorophyll.

Structures in Bacteria Cells

• Bacteria cells contain a cell membrane and cytoplasm.
• The circular chromosome (circular DNA ring) controls cell activity and is free in the cytoplasm without a nucleus.
• Plasmids are tiny circular sections of extra DNA that can be exchanged between cells.
• A flagellum, when present, is a whip-like structure used for swimming.
• A non-cellulose cell wall, made of murein, maintains cell shape and structure.

Temporary Slide Preparation

• Place cells/epidermis on a slide.
• Stain with iodine or water.
• Lower a coverslip onto the slide using a needle to avoid air bubbles.
• View under a microscope.

Resolution

• Resolution is the ability to see fine detail.

Magnification Calculation

• Convert mm measurements to micrometres (µm) by multiplying by 1000.
• Magnification = (size of image)/(size of real object)

Specialized Cells

• Specialized cells have adaptations for a particular function.
  • Examples include red blood cells, neurones, and sperm.

Biological Organization

• Tissues are groups of similar cells working together.
• Organs are made from groups of different tissues working together.
• Organ systems consist of groups of different organs working together.
• Organisms are independent living things made up of organ systems.

Exchange Surfaces and Transport Systems

• Smaller organisms have a large surface area to volume ratio, allowing them to meet requirements and remove waste through their body surface.
• Larger organisms have a smaller surface area to volume ratio, necessitating specialized exchange surfaces and transport systems to increase the rate of substance exchange.

Diffusion

• Diffusion is the movement of molecules from an area of high concentration to an area of low concentration.
• Diffusion doesn't require energy.

Factors Affecting Diffusion

• Temperature: Higher temperatures increase particle kinetic energy and diffusion rate.
• Concentration Gradient: A larger concentration gradient increases diffusion rate.
• Surface Area: A larger surface area increases diffusion rate.

Stem Cells

• Stem cells are simple cells that divide to produce more stem cells.
• They can differentiate into different specialized cells.

Embryonic Stem Cells

• Embryonic stem cells are found in embryos, umbilical cords, and placentas.
• They can differentiate into almost any type of cell.

Adult Stem Cells

• Adult stem cells are found in bone marrow.
• They can only differentiate into a limited number of cell types.

Plant Stem Cells

• Plant stem cells are found in meristems at the end of shoots and roots.
• Specialization of plant stem cells can be reversed under certain conditions.

Ethical Issues of Embryonic Stem Cells

• Harvesting stem cells from embryos results in the destruction of the embryo.
• Some people oppose this for religious reasons.

Medical Uses of Stem Cells

• Stem cells can treat leukaemia.
  • Patients receive chemotherapy and radiotherapy to destroy cancerous and healthy white blood cells, stopping bone marrow production.
  • A bone marrow transplant follows, where donor stem cells multiply and produce healthy blood cells.

Risks of Stem Cell Treatment

• Chemotherapy and radiotherapy leave patients with no immune system to fight infections.
• Donor stem cells may divide uncontrollably, producing tumors.

Photosynthesis

• Photosynthesis is an endothermic (energy-absorbing) reaction in chloroplasts of plant cells.
• Plants use energy from sunlight to convert carbon dioxide and water into glucose and oxygen.
  • Word equation: Carbon dioxide + Water -> Glucose + Oxygen
  • Balanced chemical equation: 6CO2 + 6H2O -> C6H12O6 + 6O2

Glucose Use in Photosynthesis

• Glucose is converted into starch for storage, cellulose for cell walls, chlorophyll and protein for growth.
• It is also used for respiration to provide energy.

De-Starching Plants

• Plants are de-starched by keeping them in the dark for 24-48 hours.
• Without light, plants stop producing starch, using stored starch for respiration.

Purpose of De-Starching

• Plants are de-starched before experiments to ensure any starch formed indicates photosynthesis during the experiment.

Testing a Plant for Starch

• Dip the leaf in boiling water for 30 seconds to kill it and stop chemical reactions.
• Place the leaf in hot ethanol for 10 minutes to remove chlorophyll.
• Rinse the leaf in water to soften it.
• Add iodine solution to test for starch.
  • Blue-black indicates starch presence (photosynthesis occurred).
  • Yellow-brown indicates no starch (no photosynthesis occurred).

Proving the Need for Light in Photosynthesis

• De-starch a plant.
• Cover part of a leaf with lightproof paper/foil.
• Place the plant in bright light for several hours.
• Test the leaf for starch; the covered area will test negative, and the uncovered area will test positive.

Proving the Need for Chlorophyll in Photosynthesis

• De-starch a variegated plant.
• Place the plant in bright light for several hours.
• Test the leaf for starch: areas without chlorophyll will test negative, and areas with chlorophyll will test positive.

Proving the Need for Carbon Dioxide in Photosynthesis

• De-starch a plant.
• Expose one leaf to sodium hydroxide (to absorb carbon dioxide) and another to water (control).
• Place the plant in bright light for several hours.
• Test both leaves for starch; only the leaf exposed to carbon dioxide will test positive.

Measuring the Rate of Photosynthesis

• The rate of photosynthesis measures the number of oxygen bubbles or volume of oxygen produced, when increasing the light intensity.

Factors Affecting Photosynthesis

• Light intensity, carbon dioxide concentration, and temperature affect photosynthesis.
• All factors must be at optimum levels for maximum photosynthesis rate.
• Shortage of any factor limits the rate, becoming a limiting factor.

Light/CO2 Effects on Photosynthesis

• Increasing light intensity/carbon dioxide concentration increases the rate, until a certain point where some other factor becomes limiting.

Temperature Effects on Photosynthesis

• Increased temperature causes molecules to gain kinetic energy, resulting in reactions occuring more frequently.
• Enzymes denature at very high temperatures, reducing or stopping the reaction.

Leaf Cell Parts and Functions

• Upper Epidermis: Single transparent cell layer with no chloroplasts reduces water loss and assists with physical defence.
• Waxy Cuticle: Waterproof layer reducing water loss; transparent to allow light to pass.
• Palisade Mesophyll: Tightly packed cells with many chloroplasts increase photosynthesis.
• Spongy Mesophyll: Few chloroplasts and a large surface area increase the diffusion of carbon dioxide and oxygen.
• Intercellular Air Spaces: Allow diffusion of carbon dioxide and oxygen.
• Guard Cells: Open and close stomata.
• Stomata: Small pores allowing carbon dioxide and oxygen to enter and leave the leaf.

Leaf Adaptations for Light Absorption

• Transparent waxy cuticle and upper epidermis allow light into the leaf.
• Palisade mesophyll cells at the top of the leaf have many chloroplasts.
• Thin leaves ensure all cells receive light.
• Large surface area allows the leaves to receive light.

Leaf Adaptations for Gas Exchange

• Spongy mesophyll has a large surface area to increase diffusion.
• Intercellular air spaces allow diffusion of carbon dioxide and oxygen.
• Stomata allow carbon dioxide and oxygen to enter and leave the leaf.
• Guard cells control stomatal opening and closing.

Hydrogencarbonate Indicator

• Hydrogencarbonate indicator shows changes in CO2 levels.
  • Red means normal concentration.
  • Yellow means increased concentration.
  • Purple means decreased concentration.

Hydrogencarbonate Indicator in Different Light Conditions

• In Bright Light: Photosynthesis rate exceeds respiration, releasing more oxygen than CO2, turning red to purple.
• At Dusk/Dawn: Photosynthesis and respiration rates are equal, resulting in red.
• In the Dark: CO2 is produced, leading to higher CO2 levels, changing indicator red to yellow.

Carbohydrates

• Carbohydrates provide energy and are made of carbon, hydrogen, and oxygen.
• Simple carbohydrates (sugars) are fast-acting energy sources. Examples: glucose and lactose.
• Complex carbohydrates are sources of slow-release energy. Examples: starch, cellulose, and glycogen.

Types of Complex Carbohydrates

• Cellulose: Plant cell walls make them indigestible but become fibre, assisting digestion.
• Starch: Broken down by enzymes to produce energy.
• Glycogen: used a carbohydrate store in the human body that turns into glucose as energy.

Protein

• Protein supports cells for growth and repair.
• It is also a source of energy if carbohydrate and fat reserves are low.
• Proteins are made of long chains of amino acids.
• Fish and eggs are foods high in protein.

Fats/Lipids

• Fats are made of fatty acids and glycerol and are used as a source of energy storage and insulation.
• Cheese, butter, and oils are foods high in fat.

Food Tests

Calorie Calculation

1. Measure 20cm³ of water in a boiling tube clamped in a retort stand.
2. Record the starting temperature of water. Ignite the sample with a bunsen burner and hold under the boiling tube. Keep doing this until completely burned/repeat. Record the final temperatures.

Enzymes

• Enzymes are proteins that speed up reactions without being used up.
• Enzymes are like a catalyst.

Substrate

• A substrate is a molecule that enzymes work on.
• This forms a product.

Substrate Specificity

• An enzyme's active site is complementary to the substrates shape.
• Can only 'fit' one substrate.

Lock and Key Theory

• Each enzyme only act on one substrate.
• The shape of an enzyme's active site is complimentary to the shape.

What Enzymes Are For

Inhibitors

• Inhibitors fit into the enzyme´s active site.
• They cannot break down.
• They prevent enzye-substrate complexes forming.
• Reduce Rate of reactions.

Optimum Temp & PH

• The best PH/temp is high rate of reaction and maximum possible level.

What Does Denatured Mean

• That the shape of the active site has changed and can no longer form enzyme active substrate

Temp /PH affect enzymes

• Increase temp higher the rate but high temperatures denature enzymes.

Enzyme Action

• Rate increases and concentration increases as enzymes forma active substrate.

How Temp affects enzme Acitivity

1. Label Test tubes/Solutions
2. Add Typsin solution.
3. Add 5ml
4. Place each tube in their water bath, allow for 5mins each.

Enzymes role in Digestion

• Enzymes help break down large complex insolubale cells.

Commercial Use of Enzymes

Use:

• Break Down Stains

What is the Alimentry canal

• Tube through body
• Food = move = Wave =Peristalsis

Adaptations of the lleum

• Large area
• Permeable/ thin - allows good food to transfer
• Good blood - allows the gradients.
• Villi

respiratory system

1. Nasal
2. Trachea
3. Bronchus
4. Bronchiole
5. Lung
6. Aveoli

Adaptians of Alveoli

• LArge
• Thin
• Moist
• Permeable
• Good BSupply

Breathing

• Using a model. Inspiration- Inhale Exhalation- Exhale

Exercise and Breath

• During exercise you need Oxygen - you use breathing and increase your breathing depth to get said O2

Respiration

• Resp is exerthomic that occirs in the mitocondria to release energy

What are aerobic and anaerobic equation?

• Aerobic Glucose + Oxygen = Carbon D + water + energy 6CO2 + 6H20 = 6H12O6 + O2
• Anareobic Glucose = Lack Acide + ERnergy : C2H12O6 = 2C3H6O6

Investigate Factroes

• Mix yest/ gluocose leave 30 min
• 20 mlof yearst
• Attach Bung
• Place and repeat for a few hours at diff temps

CNS

• controls and coordiantes respinsies between receptrors and effects

A Nerone

• Transoimts electrical impulses/ messages
• They release signals

Adaptations

• Atxon - long extension 1M
• Mylein Sheath - Fatty layer/speeds up npulses
• Branched Ends - allows lots of onnections

A synapses

• A 2 men Gap nerone. Functions as junction
• Allows meesges to transfer through and controls direction of messages,

Volutary ACtion

• Reflexes are auto and fast.

Reflexes Arc

• Short pathway.

Hormones

• Messengers teleases
• travel in blood too target orgrns and longer period of atcion

DIiferent Partsof The Eyes and Function

How Eyes react to light

• Dim light - radial muscles contract to dilate pupil.
• Tight - opposite.

Ciliary muscles and suspensory ligmaments

• focus a on objects

How eye reacts objectat diff ranges

• Far object
• muscles reals and ligament is tense but the tense is thin
• Near object

Home-ostatis

• process by wich body maintains constant enviroment.

Diabetes

• when soemopne cannot cnotrol bloody glocouse.

Type of Diabertes:

Excretory System

1. KIdneys- waste
2. Ureter- allows to pass
3. bladder - stores
4. uretra

Water Content

1. Edting/drinbign/repsination

• sweat

Photoprisum

• groth response of plans towards lifht

ecology

population = no of ogranism abititc Ecosytems = COMMINTU

Biotoc /Abioto cffatoar

water light temp ph - plant prefers neutral what factors can affect organisms disease and prey

Qudrt

• framw investiageting
• quadat at each coordinates count pecies

Transenct

• habitats with gradual chnages

compwition

• animal competition

foods

food ahind = energy trophi level

Source for all foods ahnods adn webs

• sun

energy

Eveyty = energy egestation move/ repos

numbers are pyroam ids

• mass

Decompsition

• proecesses ahytoc

Saphorpitic Organamsm

• Secretes eymex on dead
• absrob nutrients / extracuelly
• soil arw water

carbon cyle

1. photo - a/r ospshteis
2. feedig
3. reps
4. decomproisiton
5. fossil
6. commbustion

GLobal Warming

• gasses = heat the earths atmspehre

huam ctivitu abd bio diversity

• Defostratuin
• plant tees
• excess ferillize

Ntorgen

1. itorgen fixation " conerts irtogen ga

• Bacertiia = anerboic

4. deitfication convert nitated i n athmeos

roots

• active tran

fertilzers

contain nitrates

• eothicfication= water / pollluctions

• Nitrated incrserses

• pnat dies. oxygen die