Topics 1,2,3 & 4

  • Created by: Austinnnn
  • Created on: 26-11-18 13:44

Eukaryotic Cells

Animal Cell:

  • Cell Membrane - Controls what diffuses in & out.
  • Cytoplasm - Where most of the chem. reactions take place.
  • Nucleus - Contols the activity of cell, DNA.
  • Ribosomes - Protein Synthesis. All proteins made here.
  • Mitochondria

Plant Cell:

  • (Everything in an animal cell)
  • Chloroplasts - Contain chlorophyll which collects light enery for photosynthesis.
  • Vacuole - Filled with cell sap, helps keep cells rigid.
  • Cell Wall - Cellulose, structure amd supports cell.

Most plant & animal cells are between 0.025μm & 60μm.

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Specialised Cells

Specialised Cell = A cell adapted for a specific job.

Examples:

  • Sperm 
  • Nerve 
  • Muscle 
  • Xylem 
  • Phloem 
  • Root Hair 

Specialised cells group into tissues.

Undiferentiated Cells = Stem cells.

Embryotic Stem Cells can be any cell, undifferentiated. Adult Bone Marrow, RBC, WBC, platelets, v. painful to get. Umbilical cord, stored for later use, body cant reject its own cells.

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Cells, Tissues & Organs

Tissue = A group of cells doing the same thing. 

Eg, muscle tissue.

Organ = A group of tissues that work together to carry out a function.

Eg, Stomach

System = A group of organs that carry out a function.

Eg, Digestive System

Example, heart muscle cells > heart tissue > heart > cardiovascular system

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Microscopy

Objective Lens = to focus image of lens

Cover Slip = to be placed over specimen and protect lens.

Microscope slide = for placing specimen onto.

Light Source & Mirror = reflect light through the image and into the eye.

Scanning Electron Microscopes (SEM) use electrons, bounce off a surface, coated with gold. Images formed by scattered electrons, lower resolution than Transmission Electron Microscope (TEM).

TEM use electron beam, pass through specimen, electrons scattered, ones that pass through focused with electromagnetic coils.

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Prokaryotic Cells

Contain:

  • Cytoplasm - contains genetic material.
  • Nucleoid
  • Plasmid
  • Ribosomes
  • Flagella
  • Food Granule
  • Mesosome
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Chromosomes ,Mitosis & Binary Fission

Mitosis = cell division that produces all cells except sex cells.

In Mitosis, DNA copied (chromosomes), double chromosomes pulled apart, two genetically identical daughter cells produced.

Used by some organisms in asexual reproduction.

  • 46 chromosomes
  • creates body cells

Binary fission = mitosis for bacteria

  • No nucleus involved
  • Circular strand of DNA replicates
  • Prokaryotic Cells only!
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Therapeutic Cloning & Plant Meristems

  • Nucleus removed from human egg cell.
  • Nucleus from cell of patient, put in egg cell.
  • Egg cell is stimulated to divide, embryo forms.
  • Stem cells produced with patient's DNA.

They would not be rejected by the patient's immune system.

Plant Meristems = Plant stem cells.

Found in: tips of roots, stems, buds, xylem & phloem.

They are undifferentiated, means that you can grow a plant from a cutting. They are smaller, thin walls, large nuclei, small or no vacuole.

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Aseptic Techniques

Use sterile equipment to add bacteria to agar plate, inoculating loop or spreader to spread evenley. Seal plate shut with tape, gap for O2, incubate for 3-5 days at 25°c. Disinfect all equipment, wash hands thoroughly before and after.

Techniques:

  • Wash hands
  • Correct Clothing
  • Sterilise inoculating loop
  • Streak agar plate
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Antibiotic Resistant Bacteria & Natural Selection

1. Not all bacteria are the same.

2. Competition to survive.

3. Most resistant bacteria survive if overused or not taken enough.

4. Resistant bacteria reproduce (binary fission)

5. Pass antibiotic resistant genes on to other bacteria

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Diffusion, Osmosis, Exchange Surfaces & Active Tra

Diffusion = movement of a liquid/gas from a place of high concentration to a place of low concentration. Can be sped up by increasing temp. or conc. gradient.

Osmosis = Movement of water from a place of high concentration to a place of low concentration through a semi-permeable membrane. Membrane has small holes to let water through but nothing else.

Good exchange surfaces have:

  • Large surface area
  • Thin surface
  • Good blood supply
  • Spongy meshophyll & stomata

Active transport = the movement of substances against a concentration gradient.

Protein carriers pick up particles and move them, requires energy which is made by respiration in the mitochondria. Plants use active transport to get minerals from the soil so they have enough. Body uses it to get excess food in gut, when diffusion has reached equilibrium.

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Alveoli, Vili & Placenta

Alveoli are air sacs at the end of bronchioles, gas exchange here.

Blood in capillary goes in deoxgenated and comes out oxgenated. Large SA, moist, good blood supply. CO₂ out and O₂ in. In air = 21% O₂, 0.04% CO₂. Out air = 17% O₂, 4% CO₂

Small intestine lined with villi, thin & increase SA of intestine, speeds up diffusion. Good blood supply, moist.

Placenta has high O₂ & nutrient blood flow to baby, returns with low O₂ & nutrients with high CO₂ & waste.

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Nerve Impules

Synapse is junction between 2 neurones which electric must pass. Neurotransmitter molecules diffuse from vesicles towards receptors, high conc. > low conc.

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Digestive System

  • A) Salivary Gland
  • B) Oesophagus
  • C) Liver
  • D) Stomach
  • E) Pancreas
  • F) Small Intestine
  • G) Large Intestine                                                                                                                 
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Enzymes

Enzymes are biological catalysts.

Involved in:

  • Digestion
  • Respiration
  • Photosynthesis
  • Protein Synthesis

They are specific, only one type of substrate will fit on active site. Lock & Key hypothesis, right reactant fits the enzyme then it splits it into simpler substrates. If temp./pH is too high then denatured, too low then slower.

  • Amalyse - Starch to sugars
  • Protease - Protein to amino acids
  • Lipase - fats into Fatty Acids Glycerol.
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Bile & Balanced Diet

Enzymes in stomach work best at ≈ pH 2, intestine more at ≈ pH 7 or 8.

Bile neutralises acid in food as it travels to intestine so intestinal enzymes dont become denatured.

Balanced Diet:

  • Protein
  • Carbohydrate
  • Fats
  • Vitamins
  • Mineral Ions
  • Fibre
  • Water
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Food Tests

Starch:

  • Small piece of food, 2 drops of iodine, blue-black = starch present.

Glucose:

  • Mix 3cm³ of benedicts solution with mashed & heated sample. Traffic light colours (red=high & green=low)

Protein:

  • Mix 3cm³ of biuret's solution with mashed & heated sample, pale purple = protein

Lipid:

  • Mash food, mix with 1cm³ of with ethonol. Pour into cold water, white cloudy = lipids.
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Exercise & Lungs

Metabolic Rate = rate of chemical reactions in your cells. Affected by:

  • Gender
  • Fat:Muscle
  • Activity
  • Genes

Males need more than females, teens need more than old people, excersie = more food, temperature (hot = less energy needed to warm up).

Breathing = Body getting oxygen into the lungs for respiration.

In = take air in and absorb O₂, diaphragm down & chest up & out 

Out = get rid of CO₂, diaphragm up & chest down & in

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Circulatory System (inc. Galen & Harvey)

Double Circulatory Sytem goes to the heart twice, body > heart > lungs > heart > body.

Galen & Harvey contributed to understanding,

  • G studied animals, blood vessels carry blood not air
  • G heart pumped
  • G ideas supported by church
  • H blood is not used up
  • H heart pumped blood back and forth
  • H heart bpm
  • H valves to stop backflow
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Blood Vessels

Blood contains plasma, carries CO₂, glucose, urea, RBC, WBC & platelets.

RBC contain haemoglobin which bonds with O₂, no nucleus allows for more haemoglobin, small size & large SA mean effective for gas exchange.

WBC are immune system cells that fight pathogens, have a nucleus.

Platelets are fragments that help clot the blood, no nucleus.

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Structure of the Heart

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Inside the Heart

4 valves that make blood flow one way:

  • Semilunar Valves
  • Biscuspid
  • Tricsupid

Heart is in 2 parts, left side gets oxygenated blood, right side gets deoxygenated blood. Each have an upper atrium & lower ventricle.

Veins feed blood to atria > ventricles push blood out into arteries.

The heart can pump faster at certain times (eg. exercise)

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The Blood System

  • Blood enters the atria.
  • Atria contract, push blood into ventricles.
  • Ventricles contract, force blood out. Valves ensure correct direction of flow.
  • Blood flows to the organs through arteries.
  • Returns through veins.
  • Two seperate sides, one for lungs, one for body.

Right side

  • Pulmonary artery, only artey to carry deoxygenated blood
  • Thinner walls

Left side

  • Pulmonary vein returns blood to heart (oxygenated)
  • Goes to body via aorta (main artery leaving heart)
  • Thicker walls

Biscupid Valves prevent backflow in both sides.

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Cardiovascular Disease

Stents - open up like a balloon in arteries to unblock them of cholestrol, keeps heart beating. Effective short recovery time.

Statins - reduce bad cholestrol (LDL), increaste good cholestrol (HDL). Long term drug, taken reguarly, negative side effects (headaches, kidney failure, liver damage, memory loss), effect isnt instant.

Artifical Heart - fake heart that keeps blood pumping. Temporary, not long term, need battery, extra drugs need to be taken to thin blood so doesnt clog as easy.

Heart Valves - damaged heart valves can be replaced with biological or mechanical ones, major surgery, can cause blood clots.

Artifical Blood - "saline" is a salt solution, can keep people alive even when ⅔ of RBC are gone.

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Weight Problems

Obesity is when excess energy is stored as fat. Can lead to:

  • Arthiritis
  • Diabetes
  • High Blood Pressure
  • Heart Disease

Inheritance can:

  • effect metabolic rate
  • Increase risk of heart disease
  • Change the Fat:Muscle ratio
  • Change cholestrol levels.
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Health

Lungs deal with 12,000L of air per day.

Smoking is very dangerous to the lungs:

  • Carbon Monoxide - Poisonous gas that reduces amount of oxygen in body
  • Tar -- brown substance that is deposited in lungs, coats alveoli.
  • Nicotine - addictive drug the affects nervous system. Increase heart rate, narrows blood vessels , high blood pressure

Diet

Eating too litte, not enough nutrients, disease like anaemia or scurvy set in.

Eatin too much, excess energy builds up, effects heart, blood pressure and joint problems.

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Cancer

Caused by mitosis.. gone wrong. Incorrect genes lead to tumour growth.

Benign = stay in one place, in a membrane, not cancer.

Malignant = spreads via bloodstream, 2ndary tumours, dangerous, cancer.

Factors that increase chance of getting cancer:

  • Smoking - harnful chemicals
  • Obesity
  • HPV - cervial cancer
  • UV exposure - changes DNA through long exposure
  • Genetics
  • Radiation
  • Random chance!
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Leaf Diagram

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Leaf Adaptation & Stomata

They are:

  • Thin - decrease distance gas travels
  • Air spaces - increase speed of diffusion
  • Stomata - let gases in & out

Stomata are holes surrounded by 2 guard cells. 

When not enough water go flat & shut to keep moisture in.

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Transpiration

Plants lose water by evapourating it from the leaves, osmosis pull water from stems, stems pull roots, roots from soil. Keeps minerals coming into plant. Humidity, light, temp., wind effect speed.

Measured using potometer:

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Plant Transport & Mierals

Xylem = water, minerals, thick wall

Phloem = food, small holes in cell wall, "sieve"

Arranged in vascuar bundles.

Nutrients & Functions:

  • Nitrogen - making protein for growth
  • phosphorus - respiration and making roots
  • potassium - resportation photosynthesis
  • magnesium - making chlorophyll
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Pathogens

Pathogens = microorganism that cause disease.

Bacteria = single-celled living organisms, used in yogurts, medicine.

Viruses = v. small, cause disease in every organism, destroy cells.

Main pathogens:

  • bacteria
  • viruses
  • protista
  • fungi
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Bacteria & Virus

Viruses:

  • Size 1/1,000,000mm
  • regular geometric shapes
  • Simple organism, does not display all characteristics, protein and genetic material only.

Bacateria:

  • 1/1000mm
  • shperical, rod or comma shaped
  • single-cell, can case disease.
  • Reproduce quickly.

Fungi:

  • size varies
  • many shapes and sizes
  • fungi have the most complex structures, feed off other living things.
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