Review of Basic Chem & Cell Biology Flashcards
Explain how failure to regulate the cell cycle can lead to tumors and cancers
- when mutations occur in the cell regulation, this can cause regulation to fail
- the cell does not have the signal to stay in interphase and abnormal cell division begins
- cell division is uncontrolled and accelerated which causes the formation of tumors/neoplasm
- if/when the tumor breaks through the tissue boundary, it can enter the bloodstream and spread
- only then can the tumor turn to cancer
- benign tumors are NOT cancerous, but MALIGNANT tumors are cancerous
Distinguish between tumour and a cancer
a tumor is occurs when there is abnormal cell division (due to disrupted cell regulation)
cancer indicates a tumor, but a tumor is not always cancer
A TUMOR IS NOT A CANCER….
- they can become cancers, but tumors are not defined as cancers until the boundaries of the tumor break through the boundaries of the original tissue
- as the cells break through the tissue layer or leave the original tumor and get into the bloodstream to spread, then it is a cancer
What are the six different ways that molecules and ions can move across the cell membrane?
free diffusion,
osmotic flow,
passive vs active transport,
primary vs secondary active
transport
What is free diffusion?
a form of PASSIVE TRANSPORT
- no ATP required
- no protein assistance required
- molecules move freely across the membrane by their concentration gradient
*What is osmotic flow?
a form of PASSIVE TRANSPORT (osmosis)
- no ATP required
- movement of water down their osmotic gradients
- causes changes in volume
- osmotic pressure/force can prevent water from moving
What is passive transport?
Passive transport allows substances to move according
to their concentration (or electrochemical) gradients.
What is active transport?
Active transport uses stored energy to move ions
or molecules against a concentration gradient.
Differentiate passive transport from active transport
passive transport does not require ATP energy as molecules just move DOWN their concentration gradient
active transport requires ATP energy because molecules are moving AGAINST their concentration gradient
What is primary active transport?
- involves ATP being directly broken to move particles against their concentration gradient
“pump” protein directly breaking ATP itself to move molecules against their gradients (Na+/K+ ATP pump)
- if you see ATP being broken
What is secondary active transport?
- uses a gradient of one molecule (created using ATP) to move another molecule, but there is no ATP being directly broken =
- uses energy from the concentration gradient
no ATP being broken directly (transported using the energy from a concentration gradient of another molecule) - co-transport
What is the difference between primary and secondary active transport?
primary active transport DIRECTLY BREAKS DOWN ATP to get the energy for active transport
secondary active transport DOES NOT DIRECTLY BREAK DOWN ATP - instead it uses the gradient created by another particle
“In primary active transport, the energy is derived directly from the breakdown of ATP. In the secondary active transport, the energy is derived secondarily from energy that has been stored in the form of ionic concentration differences between the two sides of a membrane.”
Describe the five characteristics of water
- solvent - due to water’s polar nature, it is able to dissociate ionic compounds in solutions
- lubricant - since water molecules have little friction, it can be used as a lubricant between joints to reduce friction (joint fluid)
- facilitates chemical reactions - can be used as a reactant or produced as a product (dehydration synthesis or hydrolysis)
- high heat capacity - because of the hydrogen bonds, water can absorb great amounts of heat before changing forms (can absorb large amounts of energy without a great change in temperature)
- high heat of vaporization (sweating and cooling down) - surface tension - water molecules are COHESIVE, so they have a strong tendency to stick together
What is an organic compound?
a compound containing carbon, hydrogen, and usually oxygen
- carbon has 4 valence electrons and can form 4 bonds
What are the four different functional groups?
- amine -NH2
- phosphate -(PO4)2-
- carboxyl -COOH
- hydroxyl -OH
What are the four main categories of macromolecules (their monomers and polymers)
- carbohydrates (glucose, disaccharides, glycogen, starch, cellulose)
- lipids (fatty acids, glycerol, neutral fats, steroids, phospholipids)
- proteins (amino acids)
- nucleic acids (nucleotides - DNA, RNA, ATP)
Review: what is negative feedback and what is positive feedback?
negative feedback = a method of homeostatic regulation where the response triggered shuts off the initial stimulus (provides stability and linked with homeostasis)
positive feedback = accelerates a process, where the response triggered enhances or amplifies the original stimulus (moves conditions farther from the initial set-point)
The basic unit of living things is the _________
The basic unit of living things is the CELL
Name the function of the following organelles:
- Cytoskeleton
- Peroxisome
- Lysosome
- Golgi body
- Nucleus
- Smooth ER
- Rough ER
- Mitochondria
- Plasma membrane
- Ribosomes
- Cytoskeleton: creates the shape of the cell
- Peroxisome: involved in oxidative reactions
- Lysosome: fuses with incoming vesicles, digests contents, or involved in auto-digestion (“suicide sac”)
- Golgi body: packaging lysosomes, secretory vesicles, in charge of processing, packing, modifying, and sorting contents from the ER
- Nucleus: control centre of the cell, contains nucleolus, DNA, etc.
- Smooth ER: no ribosomes, synthesizes lipids (phospholipids, steroids, etc.), packages contents into transport vesicles
- Rough ER: has ribosomes, producing proteins/enzymes, packaging and sorting cargo into transport vesicles
- Mitochondria: powerhouse of the cell, produces the ATP energy for the cell
- Plasma membrane: phospholipid bilayer which separates the inside from the outside of the cell (selectively permeable)
- Ribosomes: site of protein synthesis
What is dehydration synthesis?
process by which monomers come together to form polymers
- produces water as a byproduct
A+B = C+water
What is hydrolysis?
process by which polymers break down into monomers
- uses water as a reactant
C+water = A+B
What is the cell cycle?
The Cell Cycle - divided into two phases (interphase and mitosis)
Interphase = the cell spends most of its time in interphase (normal cell activities)
Mitosis = the division of the cell
The cell cycle is usually tightly regulated
by genes and other cell biological
factors, and most cells spend most of
their time in interphase (NOT dividing)
Cells spend the majority of their time in which phase?
Interphase
What causes tumors?
If cell cycle regulation is disrupted (BY MUTATIONS)…
Abnormal cell division can occur, leading to tumors, which can become cancers
- does not have the normal signal to stay in interphase, it starts dividing, cell division in accelerated rates (TUMOR/NEOPLASM)
When does a tumor become cancerous?
a tumor becomes cancer when it infiltrates the tissue boundary and enters the bloodstream, where it can spread to other parts of the body
What is the plasma membrane?
a selectively permeable phospholipid bilayer which separates the intercellular fluid from the interstitial fluid (extracellular fluid)
What is the cytoplasm made of?
cytoplasm = cytosol + organelles = all the cell’s contents
What is intracellular fluid?
the fluid INSIDE the cell
- aka cytosol
- dominated by K+ ions
What is extracellular fluid/interstitial fluid?
the fluid OUTSIDE the cell
- dominated by Na+ (and Cl-) ions
Which ion dominates ICF?
K+
Which ion dominates ECF?
Na+ (and Cl-)
Describe each of the following methods of transport:
- Free diffusion
- No transport
- Facilitated diffusion/transport
- Passive transport
- Active transport
Free diffusion
No transport
Facilitated diffusion/transport
Passive transport
Active transport
What is diffusion, carrier-mediated transport, and vesicular transport?
- Diffusion (passive)
- movement of particles down their concentration gradient without ATP - Carrier-mediated transport (passive or active)
- movement of particles across the membrane with the help of proteins - Vesicular transport (active)
- movement of particles into and out of the cell by vesicles (endocytosis and exocytosis)
What is vesicular transport?
Vesicular Transport
is a specialized
form of ACTIVE TRANSPORT that can
move large
molecules, or many
molecules at a
time
- requires ATP
- endocytosis and exocytosis
What is osmosis?
Osmosis is a form of PASSIVE TRANSPORT in which water moves to
equalize osmolarity
on each side of a
barrier
- Water molecules can diffuse across a selectively-permeable membrane according to osmotic gradients, causing changes in volume (osmotic pressure)
What is tonicity?
Tonicity is the capability of a solution to modify the volume of cells by altering their water content
Tonicity - the osmotic gradient that is created because of the substances in the water creating the gradient
- used to describe the direction of water movement by osmosis
Isotonic
concentration of solute and water is equal on both sides
THERE IS NO NET MOVEMENT OF WATER (just moves back and forth in equilibrium)
Hypertonic
concentration of solute is greater IN THE SOLUTION
- water concentration is greater in the cell
WATER MOVES OUT OF THE CELL = shrinking, crenation
net movement of water OUTWARDS
Hypotonic
concentration of solute is greater INSIDE THE CELL
- water concentration is greater in the solution
WATER MOVES INTO THE CELL = swelling, hemolysis
net movement of water INWARDS
What is transmembrane potential?
the difference of electric potential between the interior and exterior of a cell due to the different ratios of ions that can cross (selectively permeable membrane)
- at rest, cells have a negative transmembrane potential
- larger abundance of Na+ (and Cl-) OUTSIDE
- larger abundance of K+ INSIDE
- membrane is a lot more permeability to K+ and not as much to Na+ = creates a tiny negative charge inside the cell
All cells are produced by ____________, and specialize
for different functions through _______________
All cells are produced by CELL DIVISION (MITOSIS), and specialize
for different functions through DIFFERENTIATION
