Striated Muscle Cell: Challenges the idea of autonomous, independent units, large, multi-nucleated (300mm).
Giant Algae: Challenges the idea that larger organisms are always made of many microscopic cells, unicellular, up to 100mm.
Aseptate Fungal Hyphae: Challenges the idea of discrete cells, no internal walls (“septa”), long undivided sections with continuous cytoplasm and many nuclei.
Functions of Life (Mr. H Gren):
Metabolism: Enzyme-catalyzed reactions.
Response: Interact with the environment.
Homeostasis: Maintenance and regulation of internal cell conditions.
Growth: Change in size/shape.
Excretion: Removal of metabolic waste.
Reproduction: Produce offspring (sexually or asexually).
Nutrition: Feeding by synthesis or absorption of organic matter.
Unicellular organisms carry out all functions of life.
Cell size:
Increase in cell size leads to increased chemical reactions.
Surface area affects particle entry/exit.
Volume affects material production/use.
VolumeSurfaceArea ratio gets smaller as cell gets larger.
Large cells may struggle to supply essential materials or remove waste quickly enough, while small cells overheat
Larger organisms don’t have larger cells, just more of them
Emergent properties:
Properties of a group that are not possible when elements act alone.
Interaction of individual components produces new functions.
Multicellular organisms can perform a wider range of functions compared to individual cells, more preferred over unicellular organisms
Cells form tissues and organs which become systems to perform an even wider range of functions
Stem cells:
Potential to develop into many different types of specialized cells.
Able to divide through mitotic cell division.
Self-Renewal: Continually divide.
Potency: Undifferentiated and can differentiate into different cell types.
During differentiation, certain genes are expressed, resulting in proteins for cell function.
Once differentiated, cells cannot change type (“committed”).
Necessary for embryo development: Zygote formation, increase in cell division, unique body pattern, tissues comprising of specialized cells
Stem cells can be collected from embryonic stem cells (blastocysts) and adult stem cells (bone marrow or liver)
Stem cells in therapeutic uses:
Stargardt’s Disease: Genetic, blindness in children, affects membrane protein in the retina, treated by injecting embryonic stem cells into retina cells.
Parkinson’s Disease: Degenerative disorder, loss of dopamine-producing cells, exhibit tremors, rigidity, treated by replacing dead nerve cells with dopamine-producing ones.
Ethical concerns of using stem cells:
Embryonic stem cell use involves creation and death of an embryo.
Arguments against: early stage embryos are just balls of cells lacking a nervous system, if embryos are produced deliberately, no individual that would otherwise have had the chance of living is denied the chance of life, larger numbers of embryos by IVF are never implanted and do not get the chance of life
Calculating magnification
Magnification: the size of an image of an object compared to its actual size, the formula is M=AI
Where I: Size of image, A: Actual size of object, M: magnification
1.2 Ultrastructure of cells
Prokaryotes have a simple cell structure without compartmentalization.
Eukaryotes have a compartmentalized cell structure.
Electron microscopes have a much higher resolution that light microscopes
Prokaryotic Cell Structure
Unicellular; lack membrane-bound structures.
No nucleus; single chromosome (circular dsDNA) located in the nucleoid.
Most have a cell wall outside the plasma membrane.
Domains: Bacteria and Archean.
Small size (1-10μm).
Eukaryotic Cell Structure
Complicated cell structure.
Membrane-bound organelles & compartmentalization.
Compartmentalization allows for separated chemical reactions and efficiency.
Efficiency of metabolism: Enzymes and substrates can become localized and much more concentrated
Localized conditions: Different pH and other factors can be kept at optimal levels
Toxic/damaging substances can be isolated: E.g. digestive enzymes can be isolated
Numbers of organelles can be changed depending on the cell’s requirements
Larger size (5-100μm).
Consist of both animal and plant cells
Organelle
The description, function, structure/location and if they are found in prokaryotes/eukaryotes of the following:
Cytoplasm
Cell wall
Cell membrane
Pili
Flagellum
Nucleoid Region
Endoplasmic Reticulum
Golgi Apparatus
Lysosome
Ribosome
Mitochondria
Vacuole
Nucleus
Chloroplasts
Centrosome
Plasmids
Binary Fission
For unicellular organisms, cell division is the only method used to produce new individuals. Prokaryotes reproduce asexually using the process of binary fission
The chromosome is replicated and each identical copy is moved to either end of the cell
The cell elongates. New cell wall forms and plasma membrane pinches in
Cross walls form two separate cells. The two new cells separate
Comparison between Prokaryotic vs Eukaryotic, Plant vs Animal, Light microscope vs Electron Microscope Cells
1.3 Membrane structure
Phospholipids form bilayers in water due to amphipathic properties.
Membrane proteins are diverse (structure, position, function).
Cholesterol is a component of animal cell membranes.
Phospholipids
Made up of two parts, a phosphate head and a fatty acid tail
Lipids are amphipathic
The head is hydrophilic (water-loving) and attracted to water
The tail is hydrophobic (water-hating) and is repelled by water
Arrangement in Membranes
Phospholipids are amphipathic. The phosphate head is hydrophilic and the fatty acid tails are hydrophobic. Due to this, a bilayer self-assembles in water. The phosphate heads are attracted to water. Therefore, the phosphate heads are on the outside of the bilayer. The fatty acid tails are not attracted to water and are attracted to each other. Hence, the fatty acid tails are on the inside, positioned away from the water. The surface of the bilayer is hydrophilic and the inside of the bilayer is hydrophobic
Characteristic of membranes:
Flexible: Move and form a variety of shapes.
Strong: The hydrophobic region hates water so much that the repelling nature keeps the membrane together.
Self-healing: A hole in the membrane will self-heal due to the hydrophobic region’s hatred of water.
Semipermeable: Only some solutes may pass through the membrane.
Membrane Proteins
Proteins classified as integral (permanently embedded) or peripheral (temporarily embedded).
Proteins perform various functions: junctions, enzymes, transport, recognition, anchorage, transduction.
Cholesterol
Controls membrane fluidity by making phospholipids pack more tightly.
Hydroxyl group (polar head) attracts phosphate heads.
Non-polar hydrophobic tail attracts hydrophobic tails of phospholipids.
Classified as a steroid (carbon rings).
Fluid Mosaic Model: According to a fluid-mosaic model Cell membranes are represented. Cell membrane is described to be fluid due to its hydrophobic integral components. The membrane is depicted as mosaic because like a mosaic that is made up of many different parts composed of different kinds of macromolecules such as integral proteins, peripheral proteins, glycoproteins, phospholipids, glycolipids and in some cases cholesterol and lipoproteins
Danielli and Davson Model
In 1935, Hugh Davson and James Danielli suggested a model that proposed the lipid bilayer was covered on both sides by a thin layer of protein. As electron microscopy emerged, there were some inconsistencies between new observations These observations included:
Not all membranes were symmetrical
Membranes with different functions also have a different composition, which the model did not allow for
A protein layer is not likely because it is non-polar and doesn’t interact well with water
Rejected due to:
Freeze fracture electron micrographs fracturing frozen cells allowed the outer phospholipid layer to be removed. Micrographs showed globular proteins present on the upper surface of the inner phospholipid layer
Protein extraction. Proteins extracted from the plasma membrane were globular and varied in size. Parts of their surface were hydrophobic. Suggesting proteins were embedded within the phospholipid bilayer and their hydrophobic regions could attract the fatty acid tails.
1.4 Membrane transport
Particles move across membranes by simple diffusion, facilitated diffusion, osmosis and active transport.
Tissues or organs to be used in medical procedures must have the same osmolarity
The fluidity of membranes allows for endocytosis or released by exocytosis. Vesicles move materials within cells.
Passive Transport
Diffusion: Substances move between phospholipids, larger polar molecules move through channel proteins.
Osmosis: Diffusion of water between a semi-permeable membrane, through special protein channels called aquaporins. If there was no membrane the molecules would just spread out on their own and the water would stay put.
Osmolarity is a measure of solute concentration, as defined by the number of osmoles of a solute per litre of solution.
Hypotonic solution: A word used to describe a solution that has a lower concentration of solutes
Isotonic: When the solutions on either side of the membrane is equal
Hypertonic: A word used to describe a solution that has a higher concentration of solutes
In passive transport Particles move from areas of higher concentration to areas of lower concentration (along a concentration gradient) Hence, passive transport does not require chemical energy as it is driven through by kinetic and natural energy Active Transport.
In active transport Particles move from areas of lower concentration to areas of higher concentration (against a concentration gradient) Hence, active transport requires energy through ATP and the assistance of a type of protein called a carrier protein
Size and Charge
Small & non-polar molecules move across membrane more easily than Large & polar molecules.
Sodium Potassium Pump
Active transport pump that exchanges sodium ions for potassium ions
3 Na+ ions located inside the cell bind to the carrier protein.
A phosphate group is removed from ATP and binds to the carrier protein.
The carrier protein changes shape and transports Na+ ions outside of the cell.
2 K+ located outside of the cell bind to the carrier protein.
The phosphate group is released, restoring the protein to its original shape.
The 2 K+ ions released into the cell.
Endocytosis and Exocytosis
These both create temporary holes in the cell membrane as part of the membrane is removed.
Endocytosis:
Taking in of external substances by inward pouching of the plasma membrane, forming a vesicle.
Pinocytosis (cell-drinking): Intake of extracellular fluids
Phagocytosis (cell-eating): Intake of large particles (like pathogens)
Exocytosis:
The Golgi wraps large molecules in a vesicle, then that vesicle fuses with the membrane which pushes the material to the outside of the cell.
The release of substances from a cell (secretion) when a vesicle joins with the cell plasma membrane.
1.5 The origin of cells
Cells can only be formed by division of pre-existing cells.
The first cells must have arisen from non-living material.
The origin of eukaryotic cells can be explained by the endosymbiotic theory
Spontaneous Generation
Living things can arise from non-living things
Disproved using Pasteur’s experiments
Endosymbiotic Theory
Mitochondria and chloroplast in eukaryotic cells were once independent prokaryotic cells.
Aerobic respiration and converting energy, one was capable of photosynthesis, and one was incapable of doing either of these processes. However engulphed other cells
Evidence:
Same size as prokaryotes.
Divide by binary fission.
Have their own DNA in a circular loop.
Have 70s ribosomes.
Have a double membrane (from engulfment).
Genes are more similar to prokaryotes
1.6 Cell division
Mitosis is division of the nucleus into two genetically identical daughter nuclei
Chromosomes condense by supercoiling during mitosis
Cytokinesis occurs after mitosis and is different in plants and animal cells
Interphase is a very active phase of the cell cycle with many processes occurring in the nucleus and cytoplasm
Cyclins are involved in the control of the cell cycle
Mutagens, oncogenes and metastasis are involved in the development of primary and secondary tumors
Mitosis
A process where a single cell divides into two identical daughter cells (cell division).
Growth: Multicellular organisms increase their size by increasing their number of cells through mitosis.
Asexual Reproduction: Certain eukaryotic organisms may reproduce asexually by mitosis
Tissue Repair: Damaged tissue can recover by replacing dead or damaged cells
Embryonic development: A fertilized egg (zygote) will undergo mitosis and differentiation in order to become an embryo
Cell Cycle
A series of events through which cells pass to divide and create two identical daughter cells.
Phases: interphase, mitosis and cytokinesis.
Cells spend the majority of their time in interphase
Interphase consists of:
G1 phase: increase in cytoplasm volume, organelle production and protein synthesis (normal growth)
S phase: DNA replication
G2 phase: increase in cytoplasm volume, double the amount of organelle and protein synthesis (prepare for cell division)
G0 Phase: Resting phase where the cell leaves the cell cycle and has stopped dividing. Cell carries out all normal functions without the need of dividing
Stages of Mitosis
M Phase has two parts, mitosis and cytokinesis.
Prophase:
DNA supercoil and becomes sister chromatids.
Nuclear membrane broken down.
Centrosomes move to opposite poles.
Spindle fibers begin to form.
Metaphase:
Chromatids line up in the equator.
Spindle fibers attach to the centromere of sister chromatids
Anaphase:
Spindle fibers separate the sister chromatids
The chromatids are now considered as chromosomes.
Chromosomes move to opposite poles.
Telophase:
Chromosomes uncoil to become chromatin.
Spindle fibers break down.
New nuclear membrane reforms.
Cytokinesis:
The splitting/separation of the cell immediately following mitosis.
Animal cells form cleavage furrow
Plant cells form cell plate
Cyclins
Are proteins that control the progression of cells through the cell cycle.
Cells cannot progress to the next stage of the cell cycle unless the specific cyclin reaches its threshold.
Cancer
Primary Tumor forms when carcinogens or genetic mutations cause a change to the oncogenes, oncogenes cause the cell to continously replicate and the the mass of defective cells forms a primary tumor
Secondary tumor: The tumor that forms in other parts of the body after metastasis of the primary tumor
Molecular Biology
2.1 Molecules to Metabolism
Molecular biology explains living processes chemically.
Carbon atoms can form four covalent bonds allowing a diversity of stable compounds to exist.
Life is based on carbon compounds including carbohydrates, lipids, proteins and nucleic acids.
Metabolism is the web of all the enzyme-catalyzed reactions in a cell or organism.
Anabolism is the synthesis of complex molecules from simpler molecules including the formation of macromolecules from monomers by condensation reactions.
Catabolism is the breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers
Organic Chemistry
Organic chemistry: The study of the properties and structures of organic compounds
Organic compound: A compound that contains carbon and is found in living things
All organic compounds have carbon backbones, however not all carbon compounds are organic (Ex: CO2, urea)
Carbon atoms
Carbon has four covalent bonds.
Carbon-carbon bonds strong and stable.
Carbon forms the basis of organic life.
Carbon Compounds
There are four principle groups of carbon compounds:
Carbohydrates
Lipids
Proteins
Nucleic Acids
Complex macromolecules called polymers are commonly made of smaller, recurring sub units called monomers Carbohydrates, nucleic acids and proteins are all polymers comprised of monomers, however, lipids do not contain recurring monomers
Metabolism
All chemical reactions occurring in an organism
Metabolic pathways show a sequence of chemical reactions undergone by a compound in a living organism. Most metabolic pathways consist of chains of reactions, but there are also some cycles of reactions
Anabolic reactions include photosynthesis and cellular respiration along with the synthesis of RNA and proteins, Catabolic reactions include glycolysis
Condensation/Hydrolysis
Condensation makes bonds, releases water, and is an anabolic reaction.
Hydrolysis breaks bonds, requires water, and is a catabolic reaction.
Vitalism
Vitalism was a belief that organic molecules can only be synthesized by living things Urea is an organic waste molecule produced by many living things, however, in 1800 urea was produced from inorganic chemicals proving organic molecules don’t have to be synthesized by living things.
2.2 Water
Water molecules are polar and hydrogen bonds form between them.
Hydrogen bonding and dipolarity explain the cohesive, adhesive, thermal and solvent properties of water.
Substances can be hydrophilic or hydrophobic.
Structure of Water
Two hydrogen atoms are covalently bonded to an oxygen atom.
The bond formed between the oxygen and hydrogen are referred to as a polar covalent bond
Water is also a bent molecule because the lone pair of electrons repel more than the bonds resulting in a bent structure
Hydrophilic/ hydrophobic/ Amphipathic
Hydrophobic: Molecules that are repelled to water (water hating), like Fatty acids or methane.
Hydrophilic: Molecules that are attracted to water (water loving), like carbohydrates.
Amphipathic: A molecule having both hydrophilic and hydrophobic parts, like phospholipids.
Properties of water molecules
Cohesion:
Attraction between molecules of the same type.
Surface tension that allows some organisms to rest or move on top of water’s surface
Allows water to move as a column through the stem of plants
Adhesion:
Attraction between two unlike molecules.
Water moves up the stems of plants because in addition to being attracted to itself (cohesion) it is also attracted to the side of the stem (adhesion). Water is so highly attracted to the sides of the stem that it pulls itself up against the force of gravity without any energy input from the plant
Solvent:
Water can dissolve any substance that contains charged particles (ions) or electronegative atoms (polarity).
Plant: The pholem carriea a through the tisues a flud made of water and lots of dissolves sustances
Animal: Blood carried a lot of dissolved nutrients in the plasma to different tissues in the body such as glucose, amino acids, fibrinogen and hydrogen carbonate ion
Thermal:
Water has a high specific heat capacity (amount of energy required to raise the temperature).
Cells can withstand a lot of heat energy releases from their metabolic reactions without boiling away
Sweat on the skin can absorb a lot of heat energy before it evaporates, cooling an organism
Differences in thermal properties between water and methane arise from differences in polarity between the molecules Water is polar and can form intermolecular hydrogen bonds which increases the amount of energy to break it / Methane is non-polar and can only form weak dispersion forces between its molecules.
2.3 Carbohydrates and lipids
Monosaccharide monomers are linked together by condensation reactions to form disaccharides and polysaccharide polymers
Fatty acids can be saturated, monounsaturated or polyunsaturated.
Unsaturated fatty acids can be cis or trans isomers
Triglycerides are formed by condensation from three fatty acids and one glycerol
Carbohydrates
Carbohydrate is another term for sugar. Carbohydrates can be classified into three classes depending on their complexity:
Monosaccharides: Monomers of polysaccharides, the simplest carbohydrate
Disaccharides: A molecule formed by condensation reactions between two monosaccharides
Polysaccharides: Polymers with more than 2 molecules linked together in different ways by condensation reactions
The three most important polysaccharides are: Glycogen, Starch, Cellulose
Digestion of polysaccharides involves the hydrolysis (adding water) of the bonds between the bonded monosaccharides Humans and most other animals lack the enzyme cellulase so cellulose cannot be digested in animals
Enzymes catalyze these reactions in the digestive tract of animals, including humans
Fatty Acids
Are key components of lipids in plants, animals and microorganisms
Consist of a straight chain of an even number of carbon atoms, with hydrogen atoms Fatty acids are a type of lipid
All have a methyl group (CH3) on one end and a carboxyl group (COOH) at the other end, and in the middle is a chain of anywhere between 11-23 CH2 groups
Fatty acids are not found in a free state in nature. They commonly exist in combination with glycerol in the form of triglyceride. Fatty acids can be classified as follows:
Saturated: Only have single bonds between carbon atoms, carry as many hydrogen atoms as they can, straight structure, solid at room temperature
Unsaturated: at one double bond somewhere in the chain therefore have a bent structure. They therefore packed closely together therefore are liquid at room temperature
Cis = Hydrogens are on the same side of the double bond, and they repel each other so there is a bend in the shape / Cis-fatty acids are very common in nature, bent (therefore loosely packed) and healthy
Trans = Hydrogens are on the opposite side of the double bond, so the molecule is straight / Trans-fatty acids are rare in nature, straight (therefore closely packed) and not healthy
Lipids
A diverse group of hydrophobic compounds that include molecules like fats, oils, phospholipids and steroids. Most lipids are hydrocarbons: molecules that include many non polar carbon-carbon or carbon-hydrogen bonds.
Three main types of lipids: Triglycerides, Phospholipid and Steroids
Triglycerides can either be saturated or unsaturated depending on the composition of the fatty acid chain. Animals stored at Fats, Plant stored as Oils
Health problems with lipids
Lipids can cause high cholesterol which can lead to obesity, diabetes and high blood pressure Trans-fats are mostly artificially produced / There is a positive correlation between amounts of trans- fats consumed and rates of coronary heart disease Body Mass index = Weight (in kg) / Height^2 (in m)
2.4 Proteins
Amino acids are linked together by condensation to form polypeptides
There are 20 different amino acids in polypeptides synthesized on ribosomes
Amino acids can be linked together in any sequence giving a huge range of possible polypeptides
The amino acid sequence of polypeptides is coded for by genes
A protein may consist of a single polypeptide or more than one polypeptide linked together
The amino acid sequence determines the three-dimensional conformation of a protein. Living organisms synthesize many different proteins with a wide range of functions Each individual has a unique proteome
Proteins/ Peptide Bonds
Polymers built up from small monomer molecules called amino acids.
Have an amino group (NH2) and carboxyl group (COOH) along with an R group.
Linked together in proteins by covalent bonds (peptide bonds).
Protein function
Dependent on their shape, shape determined by secondary and tertiary structure.
A structural change of a protein that results in the loss of its biological properties is called Denaturation. Denaturation can be caused by changes to heat, salinity and to pH
Enzyme names end in -ase, the function, and the four levels of protein function are outlined
2.5 Enzymes
Enzymes have an active site to which specific substrates bind
Enzyme catalysis involves molecular motion and the collision of substrates with the active site
Temperature, pH and substrate concentration affect the rate of activity of enzymes
Enzymes can be denatured. Immobilized enzymes are widely used in industry
Enzymes
Biological catalysts, increasing reaction rates without being used up.
Substrate binds to active site, products released.
Typically named after molecules they react with (substrate) and end with the -ase suffix.
Enzymes are like extremly particular, and each enzyme only binds with one particular substrate and once the enzyme finds is exaction counterpart the chemical reaction can begin also known as the lock-and-key model
Factors affecting enzymes:
Temperature: Increasing temperature increases enzyme activity, at high temperature enzymes denature.
pH levels: Increasing pH increases enzyme activity only to a certain point before denaturing.
Concentration: Increasing substrate concentration increases enzyme activity high substrate concentrations the active site of the enzyme is saturated.
Immobilized enzymes
An enzyme attached to an inert, insoluble material. There are several techniques used to immobilize enzymes Advantages and disadvantages of immobilized enzymes include:
Used in a wide variety of industrial practices such as:
Immobilized lactase can be used to produce lactose free milk Advantages of Lactose-Free Dairy products include
As a source of dairy for lactose-intolerant individuals / As a means of increasing sweetness in the absence of artificial sweeteners / To reduce crystallization of ice creams
2.6 Structure of DNA and RNA
The nucleic acids DNA and RNA are polymers of nucleotides
DNA differs from RNA in the number of strands present, the base composition and the type of pentose
DNA is a double helix made of two antiparallel strands of nucleotides linked by hydrogen bonding between complementary base pairs
Structure of nucleotides
DNA and RNA are two types of nucleic acid they are both polymers of sub-units called nucleotides
The type of pentose is ribose in RNA but deoxyribose in DNA
In both DNA and RNA there are four possible bases. Three of these are the same, but the fourth base is thymine in DNA but uracil in RNA
RNA/DNA Structure
Nucleic acids are composed of nucleotide monomers which are linked into a single strand via condensation reactions, double helix of the DNA is stabilized by hydrogen bonds between complementary pairs of bases In order for the bases to be facing each other and be able to pair the strands must be running in opposite directions. Therefore, the two strands of DNA are described as being antiparallel
RNA differs from DNA in that it has:
Ribose sugar instead of deoxyribose (Remember, these are both monosaccharides)
Uracil instead of thymine
A single stranded structure instead of a double stranded structure
2.7 DNA replication, transcription and translation
The replication of DNA is semi-conservative and depends on complementary base pairing
Helicase unwinds the double helix and separates the two strands by breaking hydrogen bonds
DNA polymerase links nucleotides together to form a new strand, using the pre-existing strand as a template
Transcription is the synthesis of mRNA copied from the DNA base sequences by RNA polymerase
Translation is the synthesis of polypeptides on ribosomes. The amino acid sequence of polypeptides is determined by mRNA according to the genetic code
Codons of three bases on mRNA correspond to one amino acid in a polypeptide. Translation depends on complementary base pairing between codons on mRNA and anticodons on tRNA
DNA Replication
The purpose of DNA replication is to produce two identical copies of a DNA molecule. This is essential for cell growth or repair of damaged tissues. DNA replication ensures that each new cell receives its own copy of the DNA. During DNA replication DNA molecules containing nucleotides from the original molecule are produced DNA is replicated using two key enzymes:
DNA Helicase. separates the two polynucleotide strands of DNA by breaking the hydrogen bonds between complementary base pairs. Each free DNA strand becomes a parent/template strands for the replication process
DNA Polymerase: links nucleotides together to form a new strand
The RNA Types
MRNA: Serves as a temporary copy of DNA and carries the DNA codes from the nucleus to the ribosome
RRNA: Makes up the ribosome
TRNA: Carries a specific amino acid to the ribosome and adds it to the growing polypeptide chain
Transcription
The synthesis of mRNA copied from the DNA base sequences by RNA polymerase transcription is not used for long-term storage (temporary copy) and can freely exist only in the nucleusThe two nucleotides are temporarily separated to the translation for transcription. Transcription uses an enzyme called RNA polymerase and a number of necessary proteins called transcription factor
Translation
The process of converting a sequence of mRNA nucleotides to a sequence of amino acids this process occurs in the cytoplasm and results in a polypeptide chain (protein)
Triplets used include:
Groups of three letters on DNA are called triplets
Groups of three letters on mRNA are called codons
Groups of three letters on tRNA has anticodons
Genetic code
Is the same triplets make the same codons which are translated into the same amino acid in every single organism on earth there for its considered to be Universal.
Polymerase Chain Reaction
Is used to amplify small samples of DNA. It is useful when only a small amount of DNA is available for testing (Example: Crime scene, samples of blood, hair), By Using this enzyme, hydrogen bonds can be broken without denaturing the polymerase enzyme
2.8 Cell respiration
Cell respiration is the controlled release of energy from organic compounds to produce ATP
ATP from cell respiration is immediately available as a source of energy in the cell. Anaerobic cell respiration gives a small yield of ATP from glucose
Aerobic cell respiration requires oxygen and gives a large yield of ATP from glucose
Cell Respiration
Is the controlled release of energy from organic compounds to produce ATP
We continuously need this energy because once ATP is used we lose all energy through heat
Carbon compounds such as glucose or fat are carefully broken down and the energy released by doing this is used to make ATP
The respiration equation is C<em>6H</em>12O<em>6+6O</em>2⟹6CO<em>2+6H</em>2O+ATP(energy)
Respiration takes place in all living cells all the time. It can be used in industries such as Carbon dioxide and the baking/ brewing industry
Glycolysis
All cellular respiration pathways begin with glycolysis literally translates into sugar breaking. It is the first step of cellular respiration and takes place in the cytoplasm (NOT in the mitochondria) and the break down starts with glucose.
Fermentation
The breakdown of organic molecules for ATP production anaerobically fermentation also takes place in the cytoplasm as it is anaerobic Oxygen Substrate Yield of ATP per glucose Products
Aerobic Respiration
If there is oxygen present organisms will undergo aerobic respiration in the mitochondria Pyruvate (from glycolysis) and oxygen enter the mitochondria and broken down during reactions called the Krebs cycle and electron transport chain. Water, carbon dioxide and ATP are generated (along with heat).
2.9 Photosynthesis
Photosynthesis is the production of carbon compounds in cells using light energy
Visible light has a range of wavelengths with violet the shortest wavelength and red the longest
Chlorophyll absorbs red and blue light most effectively and reflects green light more than other colors
Oxygen is produced in photosynthesis from the photolysis of water. Energy is needed to produce carbohydrates and other carbon compounds from carbon dioxide
Temperature, light intensity and carbon dioxide concentration are possible limiting factors on the rate photosynthesis
Photosynthesis
The synthesis of energy rich molecules (like glucose) from carbon dioxide and water using light energy is the process by which cells synthesize organic compounds from inorganic molecules (CO2 and H2O) in the presence of sunlight
The equation that shows the process of photosynthesis is the following: 6CO<em>2+6H</em>2O⟹C<em>6H</em>12O<em>6+6O</em>2
That Process requires a photosynthetic pigment (chlorophyll) and can only occur in certain organisms photosyntheses is a two step process:
The light dependent reactions convert light energy from the sun into chemical energy (ATP)
The light independent reactions use the chemical energy to synthesize