Search Results

Nervous pathway to the Neuromuscular (NMJ)

By: HWC, Views: 8259

• A nervous impulse, also called an action potential, starts from the brain or spinal cord to signal skeletal muscle cell contraction. Action potentials continue along a motor neuron to the muscle cell. • The signal to contract must cross a synapse - the neuromuscular junction (NMJ) - betwe...

Primary Active Transport - electrochemical gradient and ion transport / water movement

By: HWC, Views: 7845

Energy derived from ATP changes the shape of a transporter protein which pumps a substance across a plasma membrane against its concentration gradient An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consis...

Graded potentials - electrical characteristics and types

By: HWC, Views: 7983

• A graded potential occurs when a gated channel is opened or closed, altering ion flow through the membrane. • Changes in ion and charge distributions cause voltage changes to the resting membrane potential. • The strength of the stimulus determines the number of gated channels affect...

Osmosis - water transport

By: HWC, Views: 7837

Osmosis is the flow of water down its concentration gradient, across a semi-permeable membrane. Osmosis is an example of diffusion, which is when molecules tend to distribute themselves evenly in a space. what is a semi-permeable membrane? It is a membrane or barrier that allows some molec...

Type of Cell Junctions - Desmosome, Hemidesmosomes and Gap Junctions

By: HWC, Views: 8073

Cell Junctions: Cell junctions are found in some multi-cellular organisms. They exist of complexes and are found between cells and between cells and other structures. The junctions provide a way for cells to connect and exchange signals. What are tight junctions, desmosomes, and gap junctions...

What are the Parts of a Plant Cell?

By: HWC, Views: 6775

Every chloroplast in a plant cell is packed with stacks of flattened sacs called thylakoids. The thylakoid membranes contain chlorophyll, as well as most of the other components required for the light reactions of photosynthesis. The chlorophyll-containing structures within the membranes are c...

Types of Transport - Uniport, Antiport and Symport (Glucose and Na+K+ Transporters)

By: HWC, Views: 7386

Some transport proteins bind and transport molecules very selectively. Uniport is the transport of one solute molecule. Symport is the transports of two solute molecules in the same direction. Antiport is the transports of two solute molecules in opposite directions. 1. Glucose bin...

Bond in biological molecules (Ionic, Covalent and Hydrogen bonds)/ How atoms bond?

By: HWC, Views: 5061

Sodium atoms and chloride atoms have unfilled orbitals in their outer shells. The lone electron in the outermost shell of a sodium atom can be pulled or knocked out. This ionizes the atom. It is now a positively charged sodium ion. A chlorine atom has an electron vacancy in its outer shell and...

Oxygen transport: association and dissociation & Factors that affect hemoglobin's saturation with O2

By: HWC, Views: 7668

• The production of oxyhemoglobin can be illustrated through the following reaction: 02 + Hb-H --) Hb-02 + H+ • This equation represents the binding of oxygen to the iron ions in heme groups in hemoglobin molecules. • Oxygen binding or loading occurs at the lungs • The dissociatio...