BIOL1210 Human Biology PDF

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Biology: Human Biologystudocu/en-au/course/macquarie-university/human-biology/AssessmentsDue Task Additional infoFriday 5 March due 5pm Writing Task 4% Write 300 words on “Are humans different from other animals.Friday 23 April Reference List 16%Open on Wednesdays from week 3 onwards open until June...

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Biology: Human Biology https://www.studocu.com/en-au/course/macquarie-university/human-biology/4401682

Assessments Due

Task

Additional info

Friday 5 March due 5pm

Writing Task 4%

Write 300 words on “Are humans different from other animals.

Friday 23 April

Reference List 16%

Open on Wednesdays from week 3 onwards open until June 8

On-line Quizzes

Week 1: ATOMS TO CELLS Lecture 1: Introduction and Outline; Scientific Process; Characteristics of Living things. How do humans work? ● Human cells, organs and tissues ● Human genetics ● HUman physiology ● Human disease ● Human reproduction How do humans fit in? ● Harnessing biology:biotechnology ● Humans and the Biosphere ● Humans and biodiversity ● Human evolution Sizes of living things and their components ● Surface area to volume ratio

Lecture 2: Basic chemistry; Biological molecules. Example exam questions 1. Plants can polymerise 2. Atoms are the smallest unit of matter participating in chemical reactions. Atoms are made of subatomic particles called electrons (-) (negligible mass), protons (+) (1 atomic mass unit) and neutrons (neutral) atomic mass unit). Living things are commonly made up of oxygen (65% of total body weight), carbon (18.6%), hydrogen (9.7%) and nitrogen (3.2%). Trace elements in humans - A range of other elements are found in lower concentrations. These are often important for the activity of particular enzymes and hormones, or for physical structures in the body - Trace elements Molecules: two or more atoms joined together Two oxygens atoms joined together to make a molecule of oxygen gas Compound: two or more elements joined together DNA is a very complex molecule made up of carbon, oxygen, hydrogen, nitrogen and phosphorus

atoms Carbon has space for an additional four electrons in its outer shell. This means it can bond with up to four other atoms. This versatility allows it to form the diverse compounds found in living things WATER Water is most abundant compound in living organisms → H2O Water molecules have a slight + charge on the oxygen and a slight - charge on the hydrogen ends respectively. This allows for water’s unique properties, such as hydrogen bonding - Polarity and hydrogen bonding give water unique properties - H-bonding keeps water liquid between 0 and 100C - Water is universal solvent for charged molecules and helps chemical reactions occur - Water cohesion - H-bonding means that a large amount of energy must be gained or lost for water temperature to change significantly. This stabilizes the temperature of organisms - High heat of vaporisation moderates temperature and allows animals to cool themselves by evaporating water - Ice is less dense than water, and therefore floats: ponds freeze from the surface downwards

pH pH, at any one time, about 1 in 500 million water molecules spontaneously dissociates: -

-

H2O ←→ H+ + OH-

The H concentration in pure water as a result of this dissociation is 10 7 moles per litre (or a pH of 7). Adding more H to water raises the H concentration, and makes it more acid. Pollution with sulfur and nitrogen oxides from industrial areas causes acid rain, often at some distance from the pollution source

Glucose is an important building block for living organisms, and is also an important intermediate in biochemical pathways Polymers: large molecules that are made by joining many smaller molecules (monomers) together

Carbohydrates Composed of carbon, hydrogen and oxygen. They are a short term energy storage molecule. Sugars are simple carbohydrates, and include glucose, fructorse, and lactose. Glucose is a central metabolite in all organisms. It is released by the liver as a source of immediate energy, and is normally maintained at concentrations of about 0.1% in blood Simple sugars may be joined together in a condensation reaction to make disaccharides: Glucose + glucose → maltose Glucose + fructose → sucrose Condensation and hydrolysis Starch is the storage form of glucose in plant cells. It is found in high concentrations in bread, potatoes, rice and pasta. Glycogen is the storage form of glucose in animal cells. The liver stores glucose as glycogen, breaking it down again to release glucose when needed Cellulose is a polysaccharide that makes up plant cell walls. It has a different type of structure that animals are unable to digest. It forms the fibre, or roughage, in our diets. Animals that rely on cellulose

as a food source have symbiotic bacteria that helps digest the cellulose. Lipids Lipids are a diverse group of compounds that have the common feature of being insoluble in water. ●

● ● ●

Fats and Oils serve as long term energy storage. Fats may also insulate the body and cushion major organs against shock. Fats and oils are formed when molecules of glycerol condense with three molecules of fatty acid. Saturated fats have no double bond in their fatty acids, and tend to be solid at room temperature Phospholipids have a phosphate group replacing one of the fatty acids. They are important components of cell membranes Steroids have a complex structure of 4 carbon rings and often have hormonal activity ○ All steroid hormones are synthesized from cholesterol Phospholipid molecules are important in the formation of cell (plasma) membranes

Proteins Proteins are polymers of amino acids. Amino acids are organic molecules that have a common core and a variable “R” group. Amino acids are joined together in condensation reactions Proteins - protein functions Proteins perform many different functions: ● Structural components of bodies such as keratin (hair, fingernails), collagen (ligaments, tendons, connective tissue) or actin and myosin (muscle fibres) ● Transport, such as the oxygen carrying haemoglobin in blood, or membrane transport proteins ● Defence against diseases by the antibody proteins of the immune system ● Synthesis and Breakdown of other molecules is performed by enzymes such as amylase (breaks down starch) or alcohol dehydrogenase ● Communication is performed by protein hormones such as insulin, which controls blood glucose levels Nucleic acids DNA and RNA are nucleic acids. They are extremely long polymers of nucleotides. There are 46 DNA molecules in each human cell, in total, containing about 6 billion nucleotides. ATP (adenosine triphosphate)

Lecture 3: Cell structure; Prokaryotic and Eukaryotic cells; Cellular organelles Which of these is mismatched?

a) b) c) d) e)

Lysosomes - hydrolytic enzymes Mitochondria - cristae Flagella - microtubules Chloroplasts - thylacine Rough endoplasmic reticulum - ribosomes

Which of these is NOT true of the nucleus? a) It contains DNA b) It is bounded by a double membrane c) It is the site of RNA synthesis d) It it found in eukaryotic cells e) It is the site of most protein synthesis → robosomes Cell theory: 1. Organisms are composed of one or more cells 2. The cell is the smallest unit of life 3. Cells arise from pre-existing cells Cell structure and function Cell wall: structural support of plant cells, made primarily of cellulose Plasma membrane: boundary of cell which regulates import and export of molecules. Made of phospholipid bilayer with embedded proteins Nucleus: membrane bound body containing DNA. Site of RNA transcription Mitochondria: organelle composed of outer membrane and inner cristae, responsible for aerobic cellular respiration Chloroplast: membranous organelle responsible for photosynthesis in plants - Use solar energy to synthesize carbohydrates in the process of photosynthesis Solar energy captured by chloroplasts is stored as chemical bonds in carbohydrates. Breaking those chemical bonds in mitochondria liberates the energy in a form that is useable by cells (ATP) Respiration and photosynthesis equations light energy + carbon dioxide + water → carbohydrate + oxygen carbohydrate + oxygen → carbon dioxide + water + energy (ATP) Endoplasmic reticulum: membranes that are the site of synthesis of proteins. Transport of products by vesicle formation Ribosome: directs the synthesis of proteins from messenger RNA, made of RNA and protein subunits - The rough ER is a series of folded membranes studded with ribosomes. It is involved in protein synthesis. Products of the ER are enclosed in vesicles for transport Lysosome: vesicle containing enzymes involved in intracellular digestion Golgi apparatus: membranous saccules involved in packaging and distribution of proteins and lipids

Cytoskeleton: protein filament (actin, tubulin) responsible for cell shape and movement of organelles ● Actin ○ The length of filaments can increase or decrease by assembly or disassembly of subunits: Cell structures can be moved, or cell themselves can move using this method (eg Amoeba pseudopods) ○ Organelles can move around cells in interactions with actin. Myosin molecules attached to organelle membranes can bind to filaments, bend at the head, detach and reattach further down the filament, thus creating a “ratcheting” movement. Muscle contraction operates using parallel filaments of actin and myosin. ● Intermediate filaments ○ Intermediate filaments are intermediate in size between actin microfilaments and microtubules. They are a ropelike assembly of polypeptides that impart mechanical strength. Intermediate filaments made of keratin give mechanical strength to skin cells. ● Microtubules ○ Microtubules are hollow cylinders composed of repeating subunits of tubulin. They maintain cell shape. In concert with the motor molecules kinesin and dynein, they move organelles around the cell. ● Centrioles ○ The centrosome is composed of a pair of centrioles lying at right angles to each other, and is the site of microtubule organisation in the cell. Each centriole is composed of 9 sets of microtubule triplets. Centrioles give rise to basal bodies that organise the microtubules in cilia and flagella ● Motor Molecules ○ The motor molecules kinesin and dynein “walk” organelles along microtubule “tracks”, moving parts of the cell around Cilia and flagella: responsible for cell movement Bacteria and Archaea: Prokaryotic cells Prokaryotes are an ancient and diverse group of organisms. They differ from Eukaryotes in not having their DNA enclosed in a membrane bound nucleus, and not having membrane bound organelles. Their plasma membranes, ribosomes, and flagella are similar to those of Eukaryotes. Like plants, they have a cell wall, but composed of peptidoglycan or other compounds, not cellulose.

Week 2: CELLS IN ACTION Lecture 4: Cell functions and Membrane membranes

Which of these molecules could pass through a plasma membrane by diffusion? a) Glycogen b) Carbon dioxide c) Sodium ions d) Cholesterol e) Proteins Which of the following is not a function of proteins in cell membranes a) Binding with specific hormones b) Carrying out enzymatic reactions c) Producing cofactors d) Aiding the transport of molecules into the cell e) Acting as markers of cell identity and recognition Why Cells are small ● Substances need to be imported and exported for cells to function ● All these substance must pass through the cell membrane ● There is a maximum rate at which this passage can occur ● As a cell gets larger, its volume increases disproportionately to its surface area ● More nutrient needs to be imported and waster exported through a relatively smaller cell membrane What are the surfaces of cells made from ● A phospholipid molecules consists of two uncharged and insoluble ‘tails’, and a charged and soluble ‘head’ ● These unusual molecules are ‘bipolar’: soluble at one end and insoluble at the other Phospholipids and lipid bilayers ● Because phospholipids are bipolar, they form layers of molecules on the surface of water. A water turbulence then leads to the formation of bilayered lipids vesicles in streams, and at the seashore ● Sea foam is naturally formed vesicles Liposomes, micelles and bilayers ● The bilayer pictured here is what a small part of a cell membrane looks like Plasma membranes of cells are phospholipid bilayers, the plasma membrane contains many embedded proteins and lipids. Carbohydrate chains attached to proteins and lipids protrude from the cell. Cytoskeleton filaments are attached to the inside of the membrane. Fluid mosaic model ● Proteins are scattered throughout the plasma membrane, forming a mosaic pattern. The

membrane is also fluid, since components can migrate to different positions on the membrane. THe fluidity imparts flexibility to cells Small uncharged molecules, like water, carbon dioxide, oxygen and alcohols can freely pass through the plasma membrane. Charged molecules cannot pas the hydrophobic phase of the bilayer. Macromolecules cannot move across the membrane because they are too large Diffusion Molecules are in constant motion. This means that if molecules are concentrated in one area, they eventually become evenly distributed in the available space, because the molecules randomly move about. This is called diffusion. Transport of molecules like oxygen, carbon dioxide and water in cells is often accomplished by diffusion ● ●

Oxygen is at higher concentrations in air than it is in the capillaries: therefore oxygen diffuses into the capillaries Carbon dioxide is at higher concentrations in the capillaries than in the alveoli of the lungs:carbon dioxide diffuses out of the capillaries

Osmosis ● Water also diffuses along concentration gradients. When the gradient is bounded by a differentially permeable membrane, the movement of water through that membrane is called osmosis. Plasma membranes are differentially permeable. ● Cells must be kept in solutions that mimics their internal concentrations. In distilled water, cells swell and burst, and in highly salty water, cells dehydrate. Transport across cell membranes ● Passive means for transporting molecules across membranes include simple diffusion and facilitated diffusion. ● In facilitated diffusion, a carrier protein embedded in the plasma membrane binds a specific molecule and transports it to the inside of the cell. These proteins operate 100’s of times per second. This does not require any energy ● ● ●

Active transport is when ATP is required to transport molecules across the cell membrane. this requires energy in the form of ATP. Examples include absorption of sodium ions from urine by the kidneys, and accumulation of iodine in the thyroid gland. It allows cells to maintain internal concentrations despite changes in the external environment.

Active transport: Sodium-potassium pump The sodium potassium pump raises the potassium content inside cells, while pumping sodium molecules

outside. This pump is active in all cells but is particularly important in nerve and muscle cells. Endocytosis and Exocytosis Entry of large particles or molecules into or out of cells is accomplished by endocytosis (in) or exocytosis (out). ● ●

During endocytosis, a pit forms in the plasma membrane, enclosing the transported substance in a small vesicle. Exocytosis is the reverse of this process During phagocytosis, large particles are engulfed and a vacuole forms. The contents are digested when the vacuole fuses with a lysosome

Receptor mediated endocytosis Receptors on the membrane bind specific substances such as vitamins, hormones, lipoproteins, or antibodies. Endocytosis then allows selective entry of these substances into the cell.

Lecture 5: Cells and Tissues Bone is one type of a) Epithelium b) Skeletal tissue c) Connective tissue d) Fibrous tissue e) Collagen A single layer of rectangular-shaped cell lining a body cavity would be a) An endocrine gland b) stratified cuboidal epithelium c) Endothelial pavement d) Simple columnar epithelium e) A bed of microvilli Organising cells into tissues Tissues are made by joining cells together. Each cell in a tissue cooperates in performing one or more tasks. Organs are composed of several tissue types. For instance, the heart contains epithelial tissue, muscle tissue, connective tissue and nervous tissue Atoms Molecules Subcellular components Cells

Tissues Organs Organ systems Organism Joining cells together Cell junctions stick cells together. These junctions can be ‘tight’ or ‘loose’ and are often connected to the fibers that or ‘loose’ and are often connected to the fibers that comprise the cytoskeleton. Some specialized junctions speed up transfer of materials between cells.

Type Tight junctions

seal two cells together so liquid cannot move through the space between cells

Desmosomes

join cells together, but allow flexibility, and a gap between cells

Join two cells together in a flexible way. They are composed of specialized proteins and are attached to intermediate filaments (made of the protein keratin) that traverse the cell.

Gap Junctions

create a channel between cells so that molecules can pass quickly from one cell to another

Create a channel between adjacent cells, so that molecules can pass easily between them.

Types of tissues Epithelial tissues

have surfaces exposed to internal fluids or the environment. They cover body surfaces and line body cavities

Connective tissues

bind other tissues together and have roles in protecting, strengthening and supporting these tissues

Muscular tissues

help move parts of the body by contraction and relaxation

Nervous tissues

relay information about conditions within and

outside the body Tissue type 1: Epithelial tissue Epithelial tissues form surfaces that face the environment or are bathed in body fluids. They may be a single cell layer (simple epithelium) or multiple cell layers (stratified epithelium). There are three types of epithelial tissue: ● Squamous epithelium consists of flattened cells. It lines blood vessels and air sacs in the lungs. ● Cuboidal Epithelium is composed of cube-shaped cells. It lines kidney tubules and ovary surfaces. ● Columnar epithelium consists of long rectangular cells. Cells may have microvilli on the free surface that help in absorption in locations such as the respiratory tract and lining of the gut. A basement membrane of glycoprotein joins the epithelial tissue to the underlying connective tissue Stratified = layers The nose, mouth, esophagus, anal canal and vagina are all lined by stratified squamous epithelium. The outer skin layer contains squamous cells reinforced by the deposition of keratin, which imparts strength Glands Epithelial tissues can secrete chemical products. Such secretory tissue is known gland, and may be composed of a single epithelial cell, or many cells. Exocrine glands secrete their products into ducts or tubes. Exocrine glands produce mucus, saliva, milkd, earwax, oils and digestive enzymes amongst others. Endocrine glands secrete hormones directly from the surface of the cell into the body fluids

Tissue type 2: Connective tissue The role of connective tissue include supporting and protecting organs, binding tissues together and fat storage. Cells in connective tissue are generally not in contact but are separated by non-connective tissue called a matrix. The matrix may be solid or liquid and is transverse by elastin fibres and by collagen fibers, some of which are reticulated (highly branched)

Fibroblasts in connective tissue secrete the collagen and elastin fibers as well as modified polysaccharides Examples: ● The walls of structures such as arteries need to be tough but flexible. These properties are properties are provided by sheets of elastic fibers called elastic lamellae, shown here in the aorta ● The umbilical cord requires flexibility, coupled with strength. It needs the vascular connection between mother and fetus: connective tissues fills this role ● In tendons, fibroblasts occur in regular parallel arrangements, imparting the great mechanical and shear stren...