Module 1: Week 2 Intro to Phys Flashcards
What is a cell?
The smallest structural units of living things.
What are organelles?
LIttle Organs, Structures within the cell that have specialised shapes and functions. Organelles facilitate the metabolism of the cell.
Types of organelles can indicate:
Cell function
Cell biology is:
The study of cellular structure and function.
What are the three main parts of the cell?
Plasma membrane
Cytoplasm
Nucleus
What is the plasma membrane?
The outer layer of the cell.
What does the plasma membrane do?
Forms a selective barrier to the cell, guarding what comes in/goes out.
Helps healthy cell function.
Allows communication between cells and environment outside cell.
What is the cytoplasm?
Everything within the cell, from the nucleus to the plasma membrane.
What are two compartments of the cytoplasm?
a) cytosol (fluid)
b) organelles
Cytosol is:
Fluid inside cells: water, solutes, suspended particles
List some organelles:
Mitochondria Rough endoplasmic reticulum Smooth endoplasmic reticulum Ribosomes Golgi complex Cytoskeleton Lysosomes Peroxisomes Nucleus
What is the nucleus?
Large organelle.
Contains DNA -contains genes:genetic material/coding.
Drives cellular function.
Directs how cell reproduces.
What does a typical cell look like:
No such thing as a typical cell. Each type of cell is specialised.
What do ribosomes do and where are they found in the cell?
Ribosomes synthesise proteins, using the genetic template provided by messenger RNA.
Ribosomes are found in the cell, free. The proteins made by free ribosomes are used by the cell.
Ribosomes are found in and on the rough endoplasmic reticulum and proteins synthesised here are packaged up by the Golgi Complex and leave the cell.
What does the Golgi Complex do?
Aust Post of the cell. Accepts, modifies, sorts molecules for transport, including synthesised proteins.
What do Mitochondria do?
Powerhouse of cell - place of cell metabolism. Produces ATP (energy currency) aerobically.
What does the Smooth Endoplasmic Reticulum do?
Synthesises lipids, phospholipids and glycoproteins.
What is the plasma membrane made of?
A bilayer of phospholipids…. Hydrophilic (polar)heads outward facing, exposed to intracellular and extracellular fluid. Hydrophobic tails (non-polar) on inside of membrane.
Transmembrane proteins - passage through membrane
Cholesterol (20%) - OH group forms hydrogen bonds with hydrophilic heads - stabilises bilayer
Peripherol proteins - cell identification (outer side)
Glycolipids (5%) - in part of layer facing extracellular fluid
The cell membrane is selectively…
permeable
Two types of movement across the cell membrane:
Passive (diffusion/concentration gradients-high to low) - requiring no energy from cell
Active (active transport) - requiring ATP - protein transporters involved
Peripheral proteins are:
On the outside of the membrane - attached to polar heads. Involved in cell identification.
Transmembrane Proteins are:
Involved in transport across the plasma membrane. Go through the entire bilayer, exposed to both intracellular fluid and extracellular fluid.
Some have a constantly open channel. Others have gates that open and close.
What are three types of passive transport?
Simple diffusion
Facilitated diffusion (channel-mediated facilitated diffusion & carrier-mediated facilitated diffusion)
Osmosis
What is Channel-Mediated Facilitated Diffusion?
Charged ions such a sodum (Na+) or Potassium (k+) travel through protein channels into the cell.
What is simple diffusion?
Substances flow through membrane without requiring energy i.e oxygen, water, urea
What is carrier-mediated facilitated diffusion?
Charged ions/ larger substances (i.e. glucose) are carried across the membrane by transport proteins - the protein is like a gate, temporarily bonds with the substance, then releases into the intracellular fluid/extracellular fluid.
What is osmosis?
Diffusion of water through the plasma membrane. Water moves towards the area with highest concentration of solutes seeking equilibrium - it’s about equalising the solute concentration.
What are glycoproteins and what function do they serve?
Proteins with carbohydrate group (oligosaccharides - 2-60 monosaccharides) attached. Gives sugary coating to cell membrane = glycocalyx. Each cell has slightly differing glycoalyx. Helps with cell identification - same with lipoproteins. Help tell your cells from cells from other people (transplant) and invaders.
Protects cells from being digested by enzymes in extracellular fluid.
Attracts film of fluid around cell membrane surface - slippery. Helps RBC slip through blood vessels.
White blood cells identify invaders in the body by their…
Glycoalyx…. sugary coating created from glycoproteins cell membrane
Roles of proteins in cell membrane:
Each cell membrane proteins are different - influences membrane function.
Integral proteins can be: receptors, cellular recognition sites, enzymes, linkers (anchor proteins in membrane)
Is the inner part of the cell membrane more positively or negatively charged?
Negative! There’s an electrical gradient too!
What is a concentration gradient?
Some areas have higher concentration of solutes that’s others. Solutes generally travel down their concentration gradient, except in active transport.
What is a electrical gradient?
Where areas have different electrical charge. The charge difference is known as the membrane potential. Helps move substances across the membrane.
What is electromagnetic gradient?
Where both electical and solute gradients work to move substances across the plasma membrane - from areas of higher concentration to lower concentration.
What energy is used in passive transport (diffusion)?
Kinetic energy of substances only. No energy contributed by cell.
Simple diffusion is:
Passive
For non-polar hydrophobic molecules: oxygen, carbon dioxide, nitrogen gasses, urea, fatty acids, steroids, fat soluble vitamins, ethyl alcohol
With cell specialisation structure reflects…
function
Specialised features of nerve cells include:
Large head with long dendrites - p/u and deliver signals over large surface
Long axon - facilitates communication over large distances
High amount of rough ER - synthesises neurotransmitter molecules
Golgi Apparatus - lots of signals to package up for delivery/transport
Specialised features of sperm cells include:
bullet head - genetic info
under bullet head, area with lots of mitochondria - need high energy for swimming
Has tail for swimming
Specialised features of RBC include:
no nucleus
lots of haemoglobin - enables it to carry oxygen
shape - bio concave disc - allows cell to squeeze through narrow blood vessels/capillaries
Specialised features of skeletal muscle include:
Long shape - slim
Lots of mitochrondria - energy for muscle contraction
3 types of muscle - smooth, skeletal, cardiac
Skeletal muscle - long, slender - contracts
Multiple nuclei - need lots of genetic info to produce proteins - power muscles
How many cells in body:
100 trillion in an adult
How many different types of cells:
200
Chemical reactions (catabolism)/actions by the body that don’t require energy to occur are called:
exergonic
Chemical reactions/actions (muscular contractions/substance transport) of the body that require energy are called:
endergonic
