Reviewer for General Biology, Study notes of Biology

Download Reviewer for General Biology and more Study notes Biology in PDF only on Docsity! Chapter 1 - Biology: Exploring Life 1.1 What is life?  Biology – the scientific study of life  Cells- the structural and functional unit of life  Order – life is characterized by highly ordered structures  Reproduction – organism reproduce their own kind  Growth and Development – inherent DNA controls the pattern of growth and development of all organism  Response – respond to stimuli  Regulation – organism have regulatory mechanisms that maintain a beneficial internal environment  Evolution – organism adapt to survive 1.2 Biologist arrange the diversity of life into the three domains  Taxonomy – branch of biology that names and classifies species  Domains Bacteria and Archaea both consist of microscopic organism with relatively simple cells. The difference between the two is that Domain Archaea lives in the Earth’s extreme environment.  Domain Eukarya which consist of Kingdom Plantae, Kingdom Protists, Kingdom Fungi, Kingdom Animalia. 1.3 Life’s hierarchy  Molecule – chemical structure consisting of two or more units called atoms.  Organelle – membrane-enclosed functional structure in a cell  Cell – fundamental and structural unit of life  Tissue – group of similar cells performing a specific function  Organs and organ system – body parts that perform a specific function  Organism – an individual living thing  Population – all individual of a particular species living in a community  Community – all organism in an ecosystem  Ecosystem – all the organism in a particular area  Biosphere – all life on earth and places where it exist 1.4 What is science?  Science – a way of knowing  Data- recorded observation  Hypothesis – a proposed explanation for a set of observation  Experiment – a scientific test often carried out under controlled conditions  Theory – much broader in scope and is supported by a large and usually growing body of evidence. 1.5 Hypotheses can be tested using controlled experiments  Independent variable – factor that is manipulated by the researchers  Dependent variable – judge outcome of the experiment 1.11 Theme: life depends on the flow of information  DNA provides the master instructions for all of a cell’s function  Genes – specific sequence that encodes precise information in units of inheritance Unit 1: The life of the Cell Chapter 2: the chemical basis of life 2.1 organisms are composed of elements  Matter – anything that occupies space and has mass  Element – substance that cannot be broken down to other substances by ordinary chemical means  Compound – a substance consisting of two or more different elements combined in a fixed ratio.  Trace Elements – elements that are only present in minute amounts 2.3 atoms consist of protons, neutrons, and electrons  Atoms – the smallest unit of matter that still retains the properties of an element.  Protons – a positively charged subatomic particles (p+)  Electron – a negatively charged subatomic particles (e- )  Neutron – a subatomic particles that has no charge  Atomic Number – number of protons  Mass Number – the sum of the protons and neutrons in its nucleus  Atomic Mass – the sum of its proton and neutrons  Isotopes – same number of protons and behave identically in chemical reaction but have different number of neutrons.  Radioactive Isotope – the nucleus decays spontaneously, giving off particles and energy. 2.5 The distribution of electrons determines an atom’s chemical properties  Chemical Bond – atoms staying close because of attractions  Ionic Bond – transfer of an electron between atoms  Covalent Bond – atoms share electrons  Electrons can be located in different electron shells, each with a characteristic distance from the nucleus. 2.6 Covalent bonds join atoms into molecules through electron sharing  Molecules – consists of two or more atoms held together by covalent bonds.  Electronegativity – a measure of its attraction for shared electrons  The more electronegativity atoms will pull harder  Amino group – nitrogen bonded to two hydrogens  Phosphate group – phosphorus atom bonded to four oxygen atoms  Methyl group – carbon bonded to three hydrogen atoms 3.3 Macromolecules  Carbohydrates, lipids, proteins, and nucleic acids are the four main macromolecules.  Polymers – small molecules joining to form a chain  Monomers – building blocks of polymers  Dehydration Reaction – a reaction that removes water molecule as two molecules become bonded  Hydrolysis – a reaction that gains water molecule as molecules breaks  Enzymes – specialized macromolecules that speed up chemical reaction in cells 3.4-7 Carbohydrates  Molecules that range from small sugar molecules to large polysaccharides, such as starch molecules.  Monosaccharides - A simple sugar that constitutes the building blocks of a more complex form of sugars  Monosaccharides, particularly glucose, are the main fuel molecules for cellular work.  Disaccharide – constructed from two monosaccharide monomers by dehydration reaction, most common disaccharide is sucrose.  Polysaccharides – polymers of hundreds to thousands of monosaccharides linked together by dehydration reaction.  Starch – energy storage polysaccharide in plants  Glycogen – energy storage of glucose in animals  Cellulose – most abundant organic compound on earth  Chitin – structural polysaccharide used by insects and crustaceans to build their exoskeleton. 3.8-11 Lipids  A diverse group however classified together because of one similar trait, hydrophobic.  Fat – lipid made from glycerol and fatty acids  Unsaturated Fatty Acid – hydrocarbon chain contains one or more double bonds. It is a fat that is liquid at room temperature. It is usually referred to as oil  Saturated Fatty Acid – solid at room temp.  Trans Fat- unsaturated fat that has been converted to saturated fat by adding hydrogen (hydrogenation).  Phospholipids – major component of cell membrane, contains only two fatty acids attached to glycerol instead of three.  Steroids – lipids in which the carbon skeleton contains four fused rings  Cholesterol – common component in animal cell membrane and is also the precursor for making other steroids, including sex hormones.  Anabolic Steroids – synthetic variant of the male hormone, testosterone, it builds up muscle and bone mass in male. 3.12-14 Proteins  Protein – polymer of small building blocks called amino acids.  Proteins are composed of differing arrangements of a common set of just 20 amino acid monomers.  There are other types of proteins such as: transport protein, proteins that are embedded in the cells membrane, that transport sugar and nutrient molecules in the cell, defensive protein, immune system, signal proteins, proteins that signal other cells to help coordinate activities.  Receptor proteins, built into cell membranes, which receive and transmit signals into your cells,  Contractile proteins found within muscle cells,  Structural proteins such as collagen, which form the long, strong fibers of connective tissues  Storage proteins, which serve as a source of amino acids for developing embryos in eggs and seeds.  In the process of denaturation, a protein unravels, loses its specific shape, and loses its function.  Amino acids - an amino group and a carboxyl group  Chemical group symbolized by R, which determines the specific properties of each of the 20 amino acids used to make proteins.  Amino acid can either be hydrophilic or hydrophobic  Peptide Bond - joining the carboxyl group of one amino acid to the amino group of the next amino acid  Primary Structure – the precise sequence of amino acids in the polypeptide chain  Secondary Structure – coils or fold into local patterns  Tertiary Structure – overall 3D shape of the protein  Quaternary Structure - protein that has more than one polypeptide chain. 4.5&6 the Nucleus and Ribosomes  Nucleus – contains he cell’s genetic instructions encoded in DNA  Chromatin – appears as a diffuse mass within the nucleus  Nuclear Envelope – a double-membrane that enclosing the nucleus  Nucleolus – prominent structure in the nucleus  Ribosomes are involved in the cell’s protein synthesis  Ribosomes are the cellular components that use instructions from the nucleus, written in mRNA, to build proteins  Some ribosomes are free and are suspended in the cytosol of as cell  Bound ribosomes are attached to the outside of the endoplasmic reticulum or nuclear envelope  Ribosomes are the cellular components that use instructions from the nucleus, written in mRNA, to build proteins 4.7 The Endomembrane System  The endomembrane system includes the nuclear envelope, endoplasmic reticulum, Golgi apparatus, lysosomes, various types of vesicles and vacuoles.  Some of the membranes are physically connected and others are liked by vesicles.  Vesicle – sac made of membranes; it transport membrane.  Largest component of the endomembrane system is the Endoplasmic Reticulum (ER), an extensive network of flattened sacs and tubules.  Smooth Endoplasmic Reticulum – are important to the sythesis of lipids, including oils, phospholipids, and steroids. It is also called smooth endoplasmic riticulum because of its smooth surfacedue to the lack of ribosomes on its outer surface. It also stores calcium ions, produces enzymes that helps to process drugs, alcohol, and other possible harmful substances.  Rough Endoplasmic Reticulum – many types of cells secrete proteins produced by ribosomes attached to rough ER. Bound ribosomes that stud the outer surface of the membrane. 4.9 Golgi apparatus  Golgi apparatus – serves as a molecular warehouse and processing station of the products produced by the ER. 4.10 Lysosomes  lysosome - a membrane-enclosed sac of digestive enzymes  made by rough ER  destroy bacteria engulfed by white blood cells  fuse with other vesicles containing damaged organelles or other materials to be recycled within a cell 4.11 Vacuoles  Vacuoles – larges vesicles that have a variety of function. 4.12  Peroxisomes - are metabolic compartments that do not originate from the endomembrane system 4.13 Mitochondria harvest chemical energy from food.  Plasmodesmata – a junction that allows plant tissue to share water, nourishment, and chemical message. Chapter 5: The Working Cell 5.3 Passive transport is diffusion across a membrane with no energy  Diffusion – the tendency for a particle of any substance to spread out into the available space  Passive Transport – cell does not have to work when molecules diffuse across its membrane.  Diffusion down concentration gradients is the sole means by which oxygen enters your cells and carbon dioxide passes out of cells 5.4 Osmosis is the diffusion of water across a membrane  Osmosis – diffusion of water across a selectively preamble membrane 5.5 Water balance between cells and their surroundings is crucial to organism  Tonicity – the ability of a surrounding solution to cause a cell to gain or lose water.  Isotonic – volume remains the same  Hypotonic – solution with a solute concentration lower than of a cell  Hypertonic – a solution with a higher solute concentration  Osmoregulation – control of water balance 5.6 Transport proteins can facilitate diffusion across membrane  Facilitated diffusion – assisted passive transport  The very rapid diffusion of water into and out of such cells is made possible by a protein channel called AQUAPORIN. 5.8 Cells expend energy in the active transport of a solute  Active Transport – a cell must expend energy to move a solute against its concentration gradient.  ATP - Adenosine triphosphate, energy molecule that supplies the energy for most active transport  A cell uses and regenerates ATP continuously.  In the ATP cycle, energy released in an exergonic reaction, such as the breakdown of glucose during cellular respiration, is used in an endergonic reaction to generate ATP from ADP. 5.13 enzymes speed up the cell’s chemical reaction by lowering energy barriers  An energy barrier must be overcome before a chemical reaction can begin, this energy is call Activation Energy.  Enzymes – molecules that function as biological catalysts, increasing the rate of reaction without being consumed by the reaction. 5.14 a specific enzyme catalyzes each cellulaar reaction  Substrate – specific reactant that an enzyme acts on  Active site – a region whee the substrate fits into.  Catalytic Cycle  Optimal Conditions for Enzymes  Most human enzymes work best as 35-400C (95-104F)  The optimal pH for most enzymes is near neutrality  Cofactors  Cofactors – nonprotein helpers  Coenzymes – organic molecules 5.15 enzyme inhibition can regulate enzyme activity in a cell  Competitive inhibitor – reduces ab enzyme’s productivity by blocking substrate molecules from entering the active site  Noncompetitive inhibitor – does not enter the active site, instead it binds to a site elsewhere the enzyme, changing its shape.  Feedback inhibition. – in some reactions, the product may act as an inhibitor of one of the enzymes in the pathway that produced it Chapter 6: How Cells Harvest Chemical Energy 6.1 Photosynthesis and cellular respiration provide energy for life  Photosynthesis – energy that comes from the sun  Cellular Respiration – O2 is consumed as organic molecules are broken down to CO2 and H2O and the cell capture the energy released in ATP  Cellular respiration takes place in the mitochondria of eukaryotic cells.  In these energy conversions, some energy is lost as heat. 6.2 Breathing supplies O2 for use in cellular respiration and removes CO2  Respiration, in the breathing sense, refers to an exchange of gases. Usually an organism brings in oxygen from the environment and releases waste CO2.  Cellular respiration is the aerobic (oxygen-requiring) harvesting of energy from food molecules by cells. 6.3 Cellular respiration banks energy in ATP molecules  Cellular respiration is an exergonic (energy-releasing) process that transfers energy from the bonds in glucose to form ATP.  Cellular respiration can produce up to 32 ATP molecules for each glucose molecule, uses about 34% of the energy originally stored in glucose, and releases the other 66% as heat 6.4 The human body uses energy from ATP for all its activity  Kilocalories (kcal) – measure of the quantity of heat required to raise the temperature of 1 kilogram. 6.5 Cell capture energy from electrons “falling” from organic fuels to oxygen  Redox reaction – the transfer of electrons from one molecule to another  Oxidation – loss of electrons from one substance  Reduction – addition of electros to another substance 6.8 After pyruvate is oxidized, the citric acid cycle completes the energry-yeilding oxidation of organic molecules.  Pyruvate does not enter the citric acid cycle but undergoes some chemical grooming  a carboxyl group is removed and given off as CO2,  the two-carbon compound remaining is oxidizedwhile a molecule of NAD+ is reduced to NADH,  coenzyme A joins with the two-carbon group to form acetyl coenzyme A, abbreviated as acetyl CoA.  Then two molecules of acetyl CoA enter the citric acid cycle. 6.9 after pyruvate is oxidized the citric acid cycle completes the energy-yeilding oxidation of organic molecules  The final stage of cellular respiration is oxidative phosphorylation, which involves electron transport and chemiosmosis and requires an adequate supply of oxygen.  The arrangement of electron carriers built into a membrane makes it possible to create an H+ concentration gradient across the membrane and then use the energy of that gradient to drive ATP synthesis.  Electrons from NADH and FADH2 travel down the electron transport chain to O2, the final electron acceptor.  Oxygen picks up H+, which forms water.  Energy released by these redox reactions is used to pump H+ from the mitochondrial matrix into the intermembrane space. 6.12 Fermentation enables cells to produce ATP without Oxygen  Fermentation – a way of harvesting energy that does not need energy  Fermentation uses glycolysis  Lactic Acid Fermentation  Your muscle cells and certain bacteria can regenerate NAD+ through lactic acid fermentation, in which NADH is oxidized back to NAD+ and pyruvate is reduced to lactate.  types of Anaerobes  Obligate Anaerobes – they require anaerobic condition and are poisoned by oxygen  Facultative Anaerobes – they can make ATP either by fermentation or by oxidative phosphorylation, depending on whether O2 is available. 6.14 cells use many kinds of organic molecules as fuels for cellular respiration  Although glucose is considered to be the primary source of sugar for respiration and fermentation, ATP is generated using carbohydrates, fats, and proteins.  Fats make excellent cellular fuel because they contain many hydrogen atoms and thus many energy-rich electrons and yield more than twice as much ATP per gram as a gram of carbohydrate.  Proteins can also be used for fuel, although your body preferentially burns sugars and fats first. Chapter 7: Photosynthesis: Using Light to Make Food 7.1 Photosynthesis fuels the biosphere  Autotrophs – makes their own food  Photoautotrophs – use the energy of light to make food.  Heterotrophs – cannot make their own food but must consume plants or animals or decompose organic material 7.2 Photosynthesis occurs in chloroplast in plant cells  Chlorophyll – a light absorbing pigment in the chloroplast that plays a central role in converting solar energy to chemical energy  Mesophyll – the green tissue in the interior of the leaf  Stomata – the tiny pores of the leaves in which serves as the entry of oxygen and the exit of carbon dioxide.