Unit 1: Building Blocks of Life Flashcards
Includes: Biological molecules and reactions, Cell structure, Cell division, tissue organisation, and the microbial world (42 cards)
Describe the chemical elements that make up biological molecules
Oxygen, Carbon, Hydrogen, Nitrogen, Calcium, Phosphorus, Potassium, Sulfur, Sodium, chlorine, Magnesium
Describe how hydrogen bonding occurs e.g. in water molecules
Hydrogen Bonds are weak electrostatic bonds due to uneven distribution of electrons in some atoms. In water molecules hydrogen from one molecule bonds to another molecule’s oxygen through a hydrogen bond.
Explain the concept of monomers and polymers
Monomers are single units. Polymers are many monomers bound together.
Explain the importance of condensation and hydrolysis reactions in a range of biological molecules
Condensation reaction is a reaction in which two molecules combine to form a single molecule. A small molecule, often water, is removed during a condensation reaction. When water is removed a covalent bond is formed. I.e. When Glucose and Fructose go through a condensation reaction Sucrose is formed.
Hydrolysis reaction is a chemical reaction in which water is used to break down the bonds of a particular substance. I.e. When Sucrose goes through a hydrolysis reaction Glucose and Fructose are formed.
Explain the synthesis and breakdown of a disaccharide and polysaccharide by the formation and breakage of glycosidic bonds
Disaccharides and polysaccharides are formed when two hydroxyl groups interact to form a strong covalent bond called the glycosidic bond. Every glycosidic bond results in one water molecule being removed, thus glycosidic bonds are formed by condensation.
Describe the structure of starch and how it relates to its biological function.
Starch is an amylose(linear chain) and branched amylopectin(branched chain) Storage Carbohydrate. Starch is stored as granules in chloroplasts.
Describe the structure of glycogen and how it relates to its biological function
Glycogen is an amylose chain with more branches. This makes glycogen more compact than starch for the storage in the liver and muscle cells. Glycogen breaks down to release energy.
Describe the structure of cellulose molecules and how it relates to its biological function
Cellulose is chains of beta glucose(do not form helices like amylose chains) and are stronger. Cellulose is cross linked to form microfibrils of the cell wall.
Describe the general structure of an amino acid
Amino group(H2N), C - H, Side Chain(known as R), Carboxyl Group(CO2H)
Describe the synthesis and breakdown of dipeptides and polypeptides by the formation and breakage of peptide bonds.
When more amino acids are added to a dipeptide, a polypeptide chain is formed.
Formation of peptide bonds: Condensation reaction occurs when the OH- from the carboxylic group of one amino acid, and H- from the second amino acid’s amine group form covalent peptide bonds and release a water molecule.
Breakage of peptide bonds: Hydrolysis reaction adds the water molecule back into the amino acid to break the peptide bond.
Describe the levels of protein structure
Primary: sequence of amino acids(determined by inherited genetic information).
Secondary: elements are stabilised by hydrogen bonds between specific local sequences of amino acids the polypeptide backbone(usually are the a helix and the B strands that make up B pleated sheets).
Tertiary: elements of the secondary structure come together to form a 3-dimensional fold(overall shape is stabilised by interactions between R groups).
Quaternary: result when two or more polypeptide chains form an interacting complex.
Describe the structure and function of globular proteins including a conjugated protein
Globular proteins usually have a spherical shape caused by tightly folded polypeptide chains. The chains are usually folded so that hydrophobic groups are on the inside, while the hydrophilic groups are on the outside.
Compare the properties and functions of fibrous proteins
Fibrous proteins are formed from parallel polypeptide chains held together by cross-links. These form, rope-like fibres, with high tensile strength and are generally insoluble in water.
Collagen: the main component of connective tissue such as ligaments, tendons, cartilage.
Keratin: the main component of hard structures such as hair, nails, claws and hooves.
Silk: forms spiders’ webs and silkworms’ cocoons.
Identify the key inorganic ions that are involved in biological processes
Nitrate,Phosphate, Chloride, Calcium, Sodium, and Iron Ions
Describe the structure of a triglyceride and a phospholipid as examples of macromolecules
Triglycerides are three fatty acids joined to glycerol by an ester linkage.
Phospholipids include Hydrophobic tails(made of fatty acids and glycerol) and Hydrophilic Heads(made of phosphate and choline)
Explain the synthesis and breakdown of triglycerides by the formation and breakage of ester bonds between fatty acids and glycerol
Condensation reaction between glycerol and a fatty acid form a triglyceride. this is an ester bond that can be broken down by hydrolysis reaction.
Explain how the properties of triglycerides relate to its function in living organisms
Triglycerides are a major component of blood and covers the internal organs and protects them from physical ‘trauma’ or ‘shock’.
Explain how the properties of phospholipids relate to its function in living organisms
When phospholipids are added to water, they self-assemble into double-layered structures called bilayers. The Hydrophobic tails point toward the interior resulting in a bilayer arrangement found in cell membranes. The existence of cells depends on phospholipids.
Explain how the properties of cholesterol molecules relate to its functions in living organisms
Cholesterol, a type of steroid, is a component in animal cell membranes and a precursor from which other steroids are synthesized. Synthesised in the liver- also obtained from eating animal products. Needed for cell membranes, brain and nerve tissue, steroid hormones and Vitamin D. A high level of cholesterol in the blood clogs arteries, by forming plaques, and may contribute to cardiovascular disease.
Understand the difference between prokaryote and eukaryote cell structure
Eukaryotic cells have a nucleus and other membrane-bound compartments. Prokaryote cells are about 1um^3 while eukaryote cells are 1000x larger at about 1000um^3.
Understand the reason why eukaryote cells are compartmentalised into organelles
Eukaryote cells are compartmentalised into organelles to make diffusion of molecules take a shorter amount of time and chemical reactions occur faster.
Describe the structure and function of the main eukaryote organelles
Plasma membrane: surrounds the contents of the cell and defines its outer boundary. Acts as a barrier, Controls transport into and out of the cell, Passes signals from the environment to the cell, Connects to other cells, concentrates enzyme activity.
Mitochondria: mainly responsible for producing energy for the cell. Plastic and can change shape and move around the cell. Inner membrane contains the electron transport chain and ATP synthase molecules. Contain their own DNA
Nucleus: home to DNA and is the control centre of the cell. nuclear pores allow signals to enter the nucleus and mRNA to leave the nucleus.
Nucleolus: region within nucleus that is the site of ribosome biogenesis. Highly dynamic and can change over time.
Ribosomes make proteins(‘read’ the sequence of mRNA and link together the appropriate individual amino acids to make the protein).
Endoplasmic reticulum: Rough contains ribosomes and is the site of protein synthesis. Smooth is the site of a variety of metabolic processes such as steroid metabolism.
Golgi: made up of membranes. packages proteins into membrane-bound parcels which are then transported to other parts of the cell or for secretion.
Endosomes: membrane enclosed vesicles that are created when the plasma membrane pulls large particles into the cell. transported into the cell where they fuse with lysosomes.
Lysosomes: variety of powerful degradative enzymes that breakdown proteins and other biological molecules into their constituent parts. Part of cell’s recycling system.
Cytoskeleton: series of fibres that runs throughout the cell. Provides mechanical strength and support for cells, allows cells to change shape and move, provides the cell’s transport system to move organelles and vesicles around, separates chromosomes and splits cells in half during cell division.
Vacuole: functions as storage for water and nutrients but also helps maintain pressure on the cell wall.
Cell wall: provides more support and strength than the plasma membrane.
Chloroplasts: similar to mitochondria but in plants. make carbohydrates through photosynthesis. double membrane with own DNA
Explain the evolutionary origins of mitochondria and chloroplasts
It is thought that both mitochondria and chloroplasts were originally free-living prokaryote cells that were phagocytosed by a cell and kept rather than broken down for parts. This symbiosis between the two cells eventually evolved into the organelles we see today. This is known as the endosymbiotic theory.
Describe the structure of a light microscope and explain the function of the main components
Light source, condenser lens, specimen, objective lens, eyepiece lens, image viewed directly.
