Yr 12 Biology Mid-Year Exam Notes Part 2

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Year 12 Biology Note on Yr 12 Biology Mid-Year Exam Notes Part 2, created by gbridgland on 06/08/2014.

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MacromoleculesM6: Polysaccharides and Lipids are important macromolecules in cells and organismsLearning Objective Polysaccharides, including cellulose and chitin and Lipids contribute to the structural components of cells and organisms Polysaccharides, including, starch and glycogen and Lipids including, fats and oil contribute to energy reserves in cells Macromolecules OverviewTypes of Compounds      Elements Contained     Unit Names - Large/Small                                             Where Found/UseCarbohydrates                    C, H, O                               - Monosaccharides = Glucose(polysaccharides)                                                            - Disaccharides = Sucrose                                                                                              - Polysaccharides = Starch, Glycogen,                                                                                                 Cellulose, ChitinLipids                                     C, H, O (P)                         - Lipids (Triglycerides) = made of Glycerol                                                                                                and Fatty acids (fats and oils)                                                                                              - Phospholipids = made of two Fatty acids                                                                                                attached to a Glycerol, a Phosphate and                                                                                                Ethanolamine                                                                                              - Hormone Lipid Derivatives = Steroids and                                                                                                WaxesProteins                                C, H, O, N (S)                      Amino acids combine (20 types) to make                                                                                               polypeptides which can be either;                                                                                               - Structural = Collagen                                                                                               - Functional = EnzymesNucleic Acids                       C, H, O, N                            - DNA = Chromosomes, Genes, Nucleotides,                                                                                                   Nitrogen Base, Sugar and Phosphate

                                  PLANTS                           ANIMALS CELLULOSE STARCH CHITIN GLYCOGEN STRUCTURE  Long straight chains of glucose molecules.  This tough fibrous molecule is unable to be broken down for use by organisms, including humans Long branched chains of glucose molecules.    Chains of glucose with added N groups.  It forms a hard protective covering.   Long branched (more than starch) chains of glucose molecules. Polysaccharides stored as Glycogen in animals found mainly in liver and muscle tissue. FUNCTION Principle component of   CELL WALLS.  Provides strength to plant cells. Storage of glucose units until needed in plants.  A plant can store reserves of starch that can be easily broken down into glucose for use in cellular respiration. Found in the exoskeleton of organisms such as; spiders, insects and crustaceans. Also found in cell walls of fungi Storage of glucose units until needed in animals, (liver/muscles).  Glycogen can be broken down to increase blood glucose as the demand for energy increases.  Link S/F Straight chains gives strength to cell wall by H bonds Insoluble and branching makes it an efficient molecule to store glucose N groups aid formation of H bonds across chains hence adds to strength Readily accessible, branching makes it an efficient molecule to store glucose.  Glycogen is insoluble and thus easily stored in vacuoles and granules for rapid use by the cell. CONTRIBUTE TO STRUCTURAL COMPONENTS ENERGY RESERVES CONTRIBUTE TO STRUCTURAL COMPONENTS ENERGY RESERVES

Polysaccharides = STRUCTURE & ENERGY

Lipids = STRUCTURE & ENERGY

  PHOSPHOLIPIDS          LIPIDS (Fats & oils)                   WAXES                  STEROIDS STRUCTURE  Triglyceride with FA removed and phosphate added.  When in water these molecules tend to organise themselves in rows •Triglyceride containing glycerol and three fatty acids. •Lipids are solid at room temp =fats. •Lipids that are liquid at room temp = Oils. • Fatty tissue (Adipose tissue) consists of only a small cytoplasm surrounded by fat globules. Produced by both Plants and Animals, often acting as a protective layer. Steroids are hormones that are produced from lipids (cholesterol) and therefore are known as lipid derivatives. FUNCTION To create a semi-permeable barrier to cellular molecular movement Insulation, energy storage. Many animals(whales, seals, dolphins) have a layer of fat under the skin and around vital organs to insulate from the cold and as an energy store. Oils tend to be found in plants where they act as energy stores.  Olive oil, sunflower oil PLANTS A waxy cuticle can be found on the leaves of some plants to prevent water loss. ANIMALS Some insects have a waxy cuticle to prevent water loss.  Humans and some other animals produce wax in the ears to stop dust and prevent water penetrating the ear drum. Cholesterol is a component of animal cell membranes but NOT plant cell membranes.  It is an important precursor molecule for the production of other steroids. Link S/F Hydrophobic / hydrophilic nature of the molecule Long fatty acids chains are energy rich Hydrophobic molecule A type of lipid that includes some hormones and cholesterol CONTRIBUTE TO STRUCTURAL COMPONENTS ENERGY RESERVES CONTRIBUTE TO STRUCTURAL COMPONENTS CONTRIBUTE TO STRUCTURAL COMPONENTS

M1: The chemical unit of genetic information in most organisms is DNALearning Objective Model the structure of SNA as a double helix made up of a sequence of complementary bases joined by weak bonds attached to a background of alternating sugars and phosphates Describe the component parts of a nucleotide Understand that DNA is composed of a sequence of nucleotides Write the complementary sequence  for a segment of DNA Inherited Characteristics Chromosomes carry the genetic information for making all living things - everything from a human to a gerbil! What makes us human? What determines our gender? In all living things, characteristics are passed on in the chromosomes that offspring inherit from their parents So all human characteristics, including gender, are based on which chromosomes we inherit What are chromosomes? Chromosomes are long strands of genetic information located in the nuclei of cells Chromosomes are most visible during cell division when they replicate and look like this Homologous ChromosomesIn most cells chromosomes are matched in pairs based on their size and shape

Chromosome from female parent

Chromosome from male parent

Homologous chromsomes

Matching pairs of chromosomes are called homologous chromosomes Each pair of homologous chromosomes contains one chromosome that has been inherited from each parent The Human Karyotype

DOUBLEHELIXSHAPE

The Human Genome Project The Human Genome Project commenced in 1988 Its aim was to map the 40 000 genes (entire human genome) of one woman and one man It was completed in 2000, 3 years ahead of schedule It will take another 100 years to analyse the data collected The WCH was responsible for sequencing the DNA on chromosome 16 Benefits Cells differentiation Embryo development Evolution New diagnosis Disease prevention Treatment What is DNA? Chromosomes and their genes are made of a molecule called DNA DNA stands for Deoxyribose nucleic acid Each chromosome isa  very long molecule of tightly coiled DNA DNA molecules carry the code that controls what your cells are made of and what they do Chromatin to Chromosomes Super-coiled structure wrapped around proteins called histones Combination of DNA and histones called chromatin Just before cell division this chromatin condenses into short fat structures called chromosomes All cell division consists of two identical chromatids Structure of SNA DNA is found in the nucleus It is made up of repeating units called nucleotides Each nucleotide is made up of 3 molecules A base (A, T, G, C) A sugar (deoxyribose) A phosphate

M6

M1

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