Biology exam sem 1 yr 11

Hypotonic diffusion

A solution contains less solutes than the cell (cell concentrated) therefor the cell is more concentration so water will move into the cell

Isotonic solutions

Contain the same concentration of solutes as inside the cell. therefor no net movement of water

Active transport

requires energy output by the cell

Passive transport

requires no energy output by the cell

cholesterol in phospholipids

is interspread between the phospholipids to make the membrane more rigid and impermeable. it also maintains the mebranes fluidity as it stops the phospholipids from clumping together

cell membranes

primarily composed of phospholipids, protiens and cholesterol

lactic acid fermentation - equation

glucose → lactic acid. Pyruvics are a product of glycolosis which converted into lactic acid

Autotrophs

energy from the sun to produce food (sun)

Hetrotrophs

Organisms that cannot use the suns energy to make food

Catabolic reactions

complex molecule breaks down into a simpler one

Anabolic reactions

small molecules build up into larger molecules

polypeptide

Bond that joins long chains of amino acids together into a three dimensional shape

Lipids

molecules catagorised as fats or oils. composed of triglucerides. these molecules are made of carbon, hyrdogen and oxygen atoms

peptides

building blocks that bond together from amino acids that form chains called peptides. proteins are formed of combinations of large peptide chains - referred to as polypeptides

Amino acids

Building blocks for protein, bond together to form chains called peptides

main energy source of the body

carbohydrates are formed of carbon, hyrdrogen and oxygen atoms.

carbohydrates ratio

1:2:1

catagories of carbohydrates

sugar and starch

how enzyme activity varies with PH

charged particles on the surface of an enzyme keep the molecule folded and maintains the shape of the active site. enzymes are most active with a narrow range of PH. if the PH varies too much on either side of the optimal then the shape of the enzyme molecule is disorted = therefor decreased activity. damaged by slight changes is irreversible. extreme PH varriations cause irreversible changes

denaturation of enzyme

heat energy breaks the bonds that cause the protien to fold, which destroys the active site.

factors that affect enzyme activity

• temperature

• PH

• substrate concentration

• product concentration

• cofactors and coenzymes

• inhibitors

Lock and key model

the substrate fits into an active site that matches its shape exactly

induced fit model

more widely accepted. assumes that the active site is more flexible and can be changed by the substrate binding to it.

specify of enzymes

enzymes are specific for a particular substrate. one enzyme catalyzes one substrate. This is because the shape of the active site matches that of the substrate

enzyme - substrate complex

when an enzyme controlled reaction takes place. the enzyme and substrate become joined together for a short period of time to form an enzyme substrate complex.

substrate

is the reactant in an enzyme catalyzed reaction

active site

a certain area on the ezyme is able to attach to the reactant. the reactant in an enzyme catalyzed reaction is called the substrate. the area of the enzyme that binds to the substrate is called the active site - where the action takes place.

mechanical digestion

the process of breaking down large peices of food into smaller peices (increases surface area)

chemical digestion

the process of breaking down large polymers into smaller monomers for absorption. enzymes speed up this process

mammalian circulatory system - main functions

• transport of water oxygen and carbon dioxide

• distribution of nutrian and removal of wastes

• body temp maintaince - homeostasis

• circulation of hormones

peristalsis

the flowing contraction of muscles that moves food through the digestive system

epiglottis

flap of cartilage over treachea to prevent food from being inhailed

biochemical pathways

chemical reactions occur in cells in a series of enzyme regulated steps

enzymes - what are they?

biological catalysts present in living systems. enzymes function by providing alternaltive pathways for chemical reactions

catalyst

substrate that increases the rate of a chemical reaction without being charged itself

how is nitrgoen excerted

• urea in mammals

• ammonia in birds and reptiles

• uric acid in reptiles

in humans in the liver convert ammonia to be less toxic urea and dissolve it into blood

how is nitrogen excreted in mammals

urea

how is nitrogen excreted in birds

ammonia

how is nitrogen excreted in reptiles

uric acid

structure of the urinary system

kidneys → paired

ureters → paired

Bladder → single

urethra → single

layers of the kidney

Cortex - nephrons for filtration

Medulla - collecting layer

pelvis - collecting tubles come together

kidney function

unfiltered blood in. filtered blood out. waste removed to ureter and bladder.

diffusion

movement of molecules from an area of high concentration to an area of low concentration until and equilibrium is reached

diffusion in human body

• water concentration in cells

• salt concentration in cells

• gas exchange in lungs

• digestive system

cellular respiration - equation

glucose + oxygen → (energy released) carbon dioxide + water

photosynthesis - equation

Water + carbon dioxide →(light and chlorophyll) glucose + oxygen

endergonic reactions

releases energy. occurs when large molecules are broken down (catabolic reactions)

exogonic reactions

occurs when molecules bond to form. uses energy (anabolic reactions)

translocation

When glucose from the leaves moves to other parts in the plant .

Re-translocation

process of moving glucose from stroage (source) to other areas of the plant (sink) - in the phloem

types of adaptations

• behavioural - how acts or behaves

• phycological - how functions

• structural - how built

essential features of circulatory system

• transport

• pump

• fluid

these features along with the heart, blood and blood vessels make up the cardiovascular system

Mammalian heart

Left side: thick myocardium, blood to body, oxygenated from lungs

Right side: significantly smaller, blood to lungs, unoxygenated

heart strings

chordae tendianae

controls the opening and closing of mitrial and triscupid valvues

layers of cardiac muscle

endocardium - smooth inner

myocardium - middle

pericardium - outer membrane

Arteries

Thick walls, elastic and muscular

expand and recoil with each heartbeat

pulse waves maintain the pressure of the blood sending it in spurts towards body tissues

veins

carries blood from body cells back to heart.

thin walled, less muscle wider diameter

blood kept moving by muscular movement and in one direction by values (prevent blood moving backwards)

capillaries

extention of inner wall of arteries and veins. One cell thick for easy diffusion across cell membranes. provides large surface area over which the exchange of materials between the blood and body cells happens.

Lymphatic system

network of tissues and organs that help rid the body of toxins, waste and other unwanted materials (wastes)

primary function is to transport lymph a fluid containing infection-fighting white blood cells, throughout the body

moves fluid in one direction by contracting muscles and veins.

urinary system

purifying system for blood → removing oxidation of protein

• nitrogen excreted

sphincter

a ring of smooth muscle that constricts a passage within the body. when it relaxes it allows the substances to move through.

opens and closes passage to regulate the flow of substances (eg. bile, urine, feaces)

where are sphincters

• urinary tracts

• blood vessels

• digestive system

stops blood going backwards

stomach

mechanical and chemical digestion

• muscle contraction breaks food into smaller pecies and mizes with gastric juices (chyme)

• hydrochronic acid (PH=2)

• pepsin enzyme - breaks down protiens in food during digestion

pancreas

secretes a range of enzymes to assist with digestion - chemical digestion

secretion results in duodenum being alkaline

respiratory pigments

protiens that transport oxygen greatly increase the amount of oxygen that blood can carry. athropods and many mollecules have heamoglobin with copy and oxygen - binding conponent

most vetebrates and some in vertebrates use haemoglobin contained with erthocytes (red blood cells)

gas exchange in humans - 2 key features

humans have a high metabolic rate and so it requires a fast rate of gas exchange

1. blood transport system with red blood cells

2. a means of ventilation to get the gases to and from the fas exchange surface

what is spontaneous generation

people belived that living organisims could come into being by spontaneous generation. this was the idea non-living objects can rise to living organisims

robert hooke

invention of the microscope which led to development of classical cell theory

antoine van leevwenhoek

decided to make his own microscope. he began looking at all kind of matter. he discovered bacteria but called in “animacules”

what did antoine van leevwenhoek name bacteria

“animacules”

fundamental theories unifying all biology

1. all organisims are made of one or more cells

2. all life functions of organisims occur within cells

3. all cells come from existing cellls

Gall bladder

stores bile a substance made by the liver. bile emulsifies fat and oils to allow lipase to work more effectively.

lipase

an enzyme used to break down fats in food so they can be absorbed in the intestines. produced in pancreas, mouth and stomach

nephron - 3 functions

1. golmerular filtration of water and soultes from the blood

2. tubular reabsorption of which water and conserved molecules back into the blood

3. tubular secretion of ions and other waste products from surrounding capillaries into distil tuble

adaption

• inherited charactersistic that helps a organisim survive in its enviroment

• a random variation that occurs during reproduction resulting in a changed feature

structual adaptation

how an organisim is built or structured. physical features on both inside and outside of an organisim. maxamise the absorption and storage of water and minimise water loss

physiological adaption

how an organism functions, especially to survive abotic factors (enviroment).

Behavioural adaption

action or responce performed by an organism in reaction to a stimulus. this behaviour can help the organism itself obtain nutriants or improve its chances of survival

Phloem

• water and food

• cells have end walls with perforations

• two way flow

• takes sugars where needed in plant

• sugar

xylem

• one way flow

• water and minerals

• no end walls between cells

• thick walls stiffened with ligin

prokaryote cells

do not have a nucleus and are not membrane bound organelles. unicellular only. simpiler than eurkayotes. eg. archae, bacteria

Eukaryotic cells

Contain a nucleus and membrane bound orgenelles. can be multicellular and unicellular. eg.plant fungi, animals

Jejnum

• chemical digestion continues (some enzymes secreted)

• absorption starts to occur

• coated with villi to increase SA:V

• large SA:V here to increase amount of absorption in a small space

How an enzyme works

1. substrate binds to active site

2. chemical reaction occurs

3. changed molecules released

Endocytosis

Material engulfed by an “in folding” of the membrane into a vessicle. made of phosophlipids

exocytosis

vesicle fuses with the plasma membrane to export contents from the cell

phospholipids

a lipid with a phosphate group. they have a hydrophilic head and a hydropholic tail. in the water the phospholipids for a bilayer, this is the primary structure of all cell membranes.

Ethonol fermintation

no alcohol, anarobic

fermintation

any partial breakdown of carbohrates taking place in the absense of oxygen. aka anarobic reaction.

Factors affecting diffusion

Temperature

concentration gradient

Distance

Barriers

Nucleotides - 3 parts

1. 5 carbon sugar

2. a base of nitrogen atoms

3. an ion of phosphoric acid known as a phosphate

5 nucleic acids

guanine, adrenine, cytosine, thymine, urical

nucleic acids

• stores and carries out genetic information

• composed of nucleotides

• unlike other macromolecules nucleic acids are not obtained from foood

• all nucleic acids are made up of conbinations of nucelotides

villi

• increase SA:S

• fats transported into the lacteal

• other nutriants absorbed in capillaries, transported to liver and then rest of body

• villi absorb most of: carbs, fats, minerals, protiens and vitamens

Large intestine

• feaces stored in rectum till expelled through anal sphicter

• compacts undigested food

• absorbs water and salts

• becertia in colum produce vitamen A and K

• peristalsis pushes waste to the rectum and anus

• elimination of feaces

the role of enzymes

• molecules in cells are constantly interactin : being formed, browken down or exchanges

• an orgainism is regulated and the rate of chemical activity is maintained by enzymes. enzymes are very important to cell function

• enzymes can be used over and over again. so only small quantites of them are required

enzyme structure

• most enzymes are proteins

• a protien is a long chain of amino acids joined by peptide bonds (called a polypeptide) folded into a 3 demensional shape

ethonol fermintation

the carbon dioxide produced during resporation is what causes the dough to rise and texture or bread. ethonol produced as a biyproduct. proccess =anarbic, no oxygen required. macromolecules break down sugars in flower and produce carbon dioxide and ethonol

hypertonic diffusion

contain more soultes than the cell. therefor the water will move out of the cell into the solution.

plant cell = pladmolyzed

animal cell = shriveled