Bio U2 Key definitions

Amphipathic

Composed of both hydrophilic and hydrophobic parts

Selective permeability

Control of what/ how many molecules enter/ exit the cell

Glycoproteins

A short chain of carbohydrates (oligosaccharides) attached to proteins that aids cell adhesion and cell recognition

Glycocalyx

The extracellular surface of the phospholipid bilayer that is made up of glycoproteins and glycolipids

Solvation (with water as the solvent)

When the particles of a polar solute is separated and surrounded by hydration cells

Osmosis

The passive diffusion of water through a semi-permeable membrane from low solute conc to high solute conc, high water potential to low water potential.

Tonicity

The ability of extracellular solution to make water move in or out of the cell

Saturated fatty acids

Straight chains of phospholipids in a linear structure. Densely packed, leading to stability.
HIGH MELTING POINT

Unsaturated fatty acids

Kinks in chain of phospholipids that prevents tight packing. Fluid and flexible

LOW MELTING POINT

Ectotherms

Cold blooded organisms that adapt to low temperature, mimics the environment. Ex: fish, reptiles.

Cell-adhesion moles (CAM)

Glycoproteins that facilitate cell adhesion.

there are diff. types of CAMs for diff types of cell junctions

Cell-cell junction

Connections that allow cells to communicate with one another with transport

Gap junction

Transfer of molecules between cells

Tight junction

Seal that prevents movement or leakage of certain molecules between cells

Adhesive junction

Provides structural stability

Water potential

The potential energy of water per unit volume of water, measured in Kpa or bars. Relative to pure water which is 0 at atmospheric pressure and 20C

Solute potential

Effect of solute molecules on water. Attraction of water to solute particles.

Pressure potential

Pressure coming from inside of cell, exerted outwards against cell membrane, cell wall

ATP

Chemical energy in the form of the nucleotide adenosine triphosphate. It distribute energy in cells for metabolism, transport and movement

Cellular respiration

A system in cells for producing ATP using energy from organic compounds and is controlled by enzymes

Hydrolysis

Water is used in the process of breaking down components (e.g. removing 1 phosphate from ATP)

Metabolism

Cellular chemical reactions that synthesizes macromolecules

Response to stimuli

Reacting to changes in an environment

Homeostasis

Maintenance of internal conditions

Movement

Controlling place and position

Growth

cell grow in size and or # (in a multicellular organism)

Reproduction

Production of an offspring sexually or asexually

Excretion

Removal of metabolic waste products

Nutrition

Intake or production of nutrients

Ultrastructure

Biological entities that can only be observed with an electron microscope

Magnification

Size as appeared VS actual size

Eye piece power x objective lens power = M

Resolution

The clarity of an image. Measured by the smallest distance between 2 points that can be resolved

Cryogenic temperature

below -180 celsius

Kingdom of life

Classifications of living organisms.

Oxidation-reduction (redox) reaction

Reaction involving the transfer of electrons (donate or accept), sometimes in the form of H atoms

Photosynthesis

Light energy is transformed to chemical energy (organic compounds) through the process of photosynthesis. Needed for life processes in ecosystems

Photosystem

An array of photosynthetic pigment molecules. Acts as a reaction center in the thylakoid membrane. Found in cyanobacteria and photosynthetic molecules

Photolysis

Splitting of H2O using light energy

Chlorophyll

Photosynthetic pigments in chloroplasts. Has types a and b. drives photosynthesis

Absorption spectrum

The amount of light absorbed by a photosynthetic pigment for varying wavelengths of light

Action spectrum

Photosynthetic activity (e.g. oxygen production) against wavelength. Shows which wavelength of light is most efficient for photosynthesis

CO2 enrichment experiments

Predict future rates of photosynthesis and plant growth with varying CO2 conc. Examples: Free Air CO2 Experiment (FACE)

Chromatography

Separates pigments in a solution

Rf value (from chromatography lab)

It is the relationship between the distance a pigment moves and the distance the solvent moves. The Rf for each pigment is unique for each solvent used

Zygote

The fusion of gametes. The fertilization of gametes

Morula

A solid ball of cells after the zygote undergoes mitosis

Blastocyst

A trophoblast and inner cell mass. Differentiation of the trophoblast and ICM begins

Morphogen

Signal molecule that control differentiation pathways by changing gene expression

Stem cell

Has the c apacity to divide endlessly and differentiate along different pathways. They can proliferate and regenerate damaged cells

Totipotent

Differentiate into any type of cell. Gives rise to complete organism. E.g. early stage animal embryo, morula

Pluripotent

Differentiate into any body cells. Can’t give rise to a whole organism. E.g. inner cell mass of the blastocyst

Multipotent

Differentiate into closely related body cell types. Aka adult stem cells. E.g. umbilical cord stem cells

Unipotent

Differentiate into their associated cell type. E.g. liver stem cells make liver cells

Stem cell niche

The microenvironment where adult stem cells are found

Differentiation

the process by which a cell becomes very specialized to carry a particular function

Neurons

nerve cells that send and receive signals

Neurotransmitter

Chemical signals released from neurons and function to transmit signals from neuron to neuron 

Membrane resting potential

When the membrane exterior and interior is polarized (Na+ inside, K+ outside), because Na K pumps pump ions across the axon membrane. is prepared for an electrical impulse.

Membrane action potential

Waves of depolarization and repolarisation in the axon

Myeline

An insulator sheath around the axon that amplifies the effect of the ion concentration gradients (faster, mor efficient transmissions).

Made of fatty acids.

Prevent degradation.

Is not continuous, has nodes of ranvier. 

Presynaptic axon

Axon from the neuron sendign the signal

Postsynaptic axon

Axon of the neuron receiving the signal

Neuromuscular junction 

A specialized synapse that connects a motor neuron to a muscle fiber. 

Effector cells

Cells in muscles, glands and organs that respond to nerve stimulus 

Gated ion channels 

Receive synaptic transmissions.

Has two types: neurotransmitter (ligand) or voltage gated 

Neonicotinoid  

Agricultural drug to kill insects. Binds to nicotinic acetylcholine receptors. Muscle contractions --> convulsion --> paralysis --> death. 

Local ion currents 

Diffusion along the exterior and interior of the axon, causing the propagation of depolarization in a wave. 

Saltatory conduction 

The propagation of action potential along the myelinated axon from node to node.

Exogenous molecules 

Molecules from the environment that can have an effect on the body 

Summation (aka neuron math) 

Multiple presynaptic neurons interact with one post synaptic neuron to have a cumulative inhibitory and excitatory effect. Is an “all of nothing” consequence of depolarization. 

Sensory neurons 

Free nerve endings found in the skin and in internal organs to sense pain. Response to stimulations. 

Emergent properties 

New feature that arise from the interaction of components 

Consciousness  

A property that emerges from the interaction of individual neurons in the brain 

Indirect active trasnport

Using a cotransporter protein, movement of one type of solute down its concentration gradient drives the movement of another solute against its concentration gradient. ATP is used to setup concentration gradient of one solute.