IB Bio SL Review

Hydrogen bond

An weak inter-molecular force between oppositely charged poles of separate molecules.

Coolant

A substance that can cool down or regulate the temperature of a system.

Particle

General term for any atom, ion or molecule.

Simple diffusion

The passive movement of a particle from an area of high concentration to low concentration.

Passive transport

Any transport mechanims which does not require energy from the cell

Active transport

Any transport mechanism which requires energy from the cell produced in cellular respiration.

Facilitated diffusion

The passive movement of a particle down its concentration gradient and through a channel protein in the phospholipid bilayer.

Osmosis

The movement of a molecule from a hypotonic solution to a hypertonic solution.

Hypotonic

A solution that has a lower solute concentration relative to another solution.

Hypertonic

A solution that has a higher solute concentration relative to another solution.

Isotonic

A solution that has the same solute concentration as another solution.

Solution

Solvent + Solute

Solvent

A substance that can dissolve another compound

Solute

A compound that is dissolved by the solvent.

Phospholipid

A type of lipid that contains a hydrophilic phosphate head and a hydrophobic tail.

Hydrophobic

Water-hating, non-polar substances

Amphipathic

Containing both hydrophobic and hydrophilic parts

Singer-Nicolson Fluid Mosaic Model

The current model of membrane structure

Davson-Danielli Model of membrane structure

A previous model of membrane structure, shown by evidence to be incorrect.

molecular formula of a phospholipid

A cell will lose water to the environment or surrounding medium

if the salt concentration outside the cell is higher then it is inside

A cell will gain water from the environment or surrounding medium

if the salt concentration outside the cell is lower then it is inside

the type of bond that exists between the 2 hydrogen atoms and the oxygen atom in a water molecule

polar covalent

Nutrients

substances that provide nourishment essential for the maintenance of life and for growth.

Essential Nutrients

Cannot be made, must be taken in

Non-essential Nutrients

Can be produced or replaced and not required in the diet

- carbohydrates (energy can be from protein or lipids)
- vitamin D & K
- saturated fatty acids
- some amino acids

Appetite control centre

hypothalamus, responsible for making us feel satisfied

Essential Amino Acids

the amino acids that a human cannot synthesize must be obtained through food

Starvation

severe or total lack of nutrients

Malnutrition

lack of proper nutrition can be the result of deficiency, imbalance or excess nutrients

Hypertension

excessively high blood pressure

Cholesterol

steroid that is synthesized in the liver and found mainly in foods of animal origin.

part of the cell membrane, regulates fluidity

High density lipoproteins

"good" cholesterol that carries cholesterol from the cells to the liver for removal from the body

Low density lipoproteins

'bad cholesterol' increases chlotesrol levels in the blood, can clog up arteries, causing blockages, or stroke.

Function of starch in plants

storage of glucose/energy in plants
and storage form that does not draw water

Structure of starch in plants

polysaccharide composed of glucose molecules
ex: amylose which is a linear/helical molecule
and amylopectin which is a branched molecule

saturated fat

carbon atoms all joined by single bonds / have no double bonds / have no increase in number of hydrogen atoms possible; tend to be straight

monounsaturated fat

one double bond in carbon chain of the fatty acid/ could add two hydrogens in the carbon chain; tend to be bent

polyunsaturated fat

two/more double bonds in the carbon chain of the fatty acid, tend to be bent

type 1 diabetes

disorder in which the body cannot produce enough insulin

type 2 diabetes

progressive disorder in which body cells become less responsive to insulin, associated with obesity

Insulin

hormone produced by the pancreas that lovers blood glucose levels

Glucagon

A hormone secreted by the pancreas that increases blood glucose

Environment benefits: of GMO's

*pest-resistant crops can be made
*so less spraying of insecticides/pesticides
*less fuel burned in management of crops
*longer shelf-life for fruits and vegetables so less spoilage
*greater quantity/shorter growing time/less land needed
*increase variety of growing locations / can grow in threatened conditions

Environment risks of GMOs

*non-target organisms can be affected
*genes transferred to crop plants to make them herbicide resistant could spread to wild plants making super-weeds
*GMOs (encourage monoculture which) reduces biodiversity
*GM crops encourage overuse of herbicides

Health benefits of GMOs

*nutritional value of food improved by increasing nutrient content
*crops could be produced that lack toxins or allergens
*crops could be produced to contain edible vaccines to provide natural disease resistance

Health risks of GMOs

*proteins from transferred genes could be toxic or cause allergic reactions
*antibiotic resistance genes used as markers during gene transfer could spread to «pathogenic» bacteria
*transferred genes could cause unexpected/not anticipated problems
OR
health effects of exposure to GMO unclear

mitochondria

aerobic cellular respiration, ATP production

Rough Endoplasmic Reticulum function

synthesis and transport of proteins; (both needed)

plasma membrane function

controls entry and exit of materials/substances in cell

free ribosome function

site of synthesis of proteins for use in the cell

Cell Theory

Idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells

Unicellular organism

Organism that consists of one cell that carries all functions of life

Metabolism

Chemical reactions inside a cell, such as cell respiration

Homeostasis

The ability to keep conditions inside the organism within tolerable limits

Scale bar

measure the size of the scale bar and divide by the magnification

Multicellular organisms

Organisms that consist of multiple cells that each have specific functions

Cell differentiation

Development of cells in different ways to perform different functions

Emergent properties

Properties that arise from the interaction of component parts. "The whole is greater than the sum of its parts."

Eukaryotic cell

Cells for a eukaryotic organism that have complicated, internal structures that are enclosed within membranes

Prokaryotic cell

Cells that do not have nucleus or any membrane-bound organelles

Cell wall

Found in plants, fungi and bacteria, they have an outer layer, are rigid and strong and made of cellulose. They are there for support, protection and allow chemicals to diffuse in and out of the cell

Cytoplasm

Material that contains enzymes that catalyse the chemical reactions of metabolism, it supports and protects cell organelles

Pili

Hair-like structures that project from the cell wall, they can be ratcheted in and out and can by used to pull cells together when connected to another bacterial cell

Flagella

Solid protein structures that protrude from the cell wall, they are used mostly for mobility

Nucleoid

Region of the cytoplasm that contains naked DNA, found only in prokaryotic cells

Naked DNA

DNA that does not have a nuclear envelope and 'floats'

Binary fission

Method of cell division for prokaryotic cells that is used for asexual reproduction

Nucleus

Organelle where cell activity is controlled it contains hereditary information of the cell

70s vs 80s ribosomes

Prokaryotes have 70s ribosomes, eukaryotes have 80s ribosomes.

Plant cell

Cell wall with an inner plasma membrane, chloroplasts that photosynthesize, carbohydrate storages of starch, large fluid-filled vacuoles that are surrounded by a membrane (tonoplast), it controls the movement of substances from the cytoplasm, they have a fixed shape that is usually irregular

Animal cell

Only have a plasma membrane, no chloroplast present, carbohydrate storages of glycogen, only have small temporary vacuoles, they have a flexible shape but are usually rounded

METABOLISM

Chemical reactions inside the cell, including respiration to release energy

NUTRITION

Obtaining food, to provide energy and the materials needed for growth

GROWTH

An irreversible increase in size

RESPONSE

The ability to react to changes in the environment

EXCRETION

Getting rid of the waste products of metabolism

REPRODUCTION

Producing offspring either sexually or asexually

Cell

Basic unit of life.

Organelle

A discrete structure within a cell that performs a specific function.

Hyphae

Filaments or threads within a fungus.

Stem cells

Cells that are able to differentiate into any other type of cell.

Differentiation

The process of cells specialising in multicellular organisms. Requires cell division and controlled gene expression.

Photosynthesis

A chemical reaction that produces organic compounds from CO2 using light energy.

Chlorophyll

A pigment protein in chloroplasts that traps light energy for use in photosynthesis.

Photolysis

A process that uses light energy to split a water molecule into Oxygen and Hydrogen. Splitting releases an electron that can be used in future reactions.

Limiting Factor

Any factor that slows down the rate of reaction when it is reduced.

Wavelength

The distance between two peaks of a wave.

Cell respiration

A chemical reaction that releases energy inside cells to produce ATP

Adenosine Triphosphate (ATP)

The energy currency inside cells and is manufactured during respiration.

Adenosine Diphosphate

One of two molecules formed when ATP is used inside cells. The other is inorganic phosphate P04-

Aerobic respiration

Respiration that occurs in the presence of oxygen.

Anaerobic respiration

Respiration that occurs in the absence of oxygen.

Ethanol

A compound that is one of the waste products of anaerobic respiration in yeast.

Carbon dioxide

A compound that is a waste product of anaerobic respiration in yeast and aerobic respiration in animals.

Lactate

A compound that is the waste product of anaerobic respiration in animal cells.

Glycolysis

A chemical reaction in respiration where glucose is broken into two pyruvate molecules. It occurs in the cytoplasm.

Pyruvate

An intermediate compound in respiration that can be broken down in the mitochondria in aerobic respiration or in the cytoplasm in anaerobic respiration.

Species

Organisms that are able to interbreed to produce fertile offspring

Reproductive Isolation

An inability to interbreed.