Week 2/3: Cells & Cellular Function Flashcards
Histology
Study of tissues
Endocytosis
Cell membrane engulfs larger molecule to bring into cell
Exocytosis
cell vescicular process that releases material outside of cell
Endocytosis Types
- Phagocytosis
- Pinocytosis
- Receptor Mediated Endocytosis
Phagocytosis
“Cell-Eating” is the process of engulfing particles such as bacteria, dust, and cellular debris. Only occurs in specialized cells.
Example: Neutrophils (a class of white blood cells) protect the body from infection by phagocytozing and killing bacteria
Phagosome
a vesicle in the cytoplasm surrounded by a unit membrane- this forms via phagocytosis
Pinocytosis
“Cell Drinking” is the process of taking in droplets of ECF (extracellular fluid) containing molecules of some use to the cell. The process begins as the plasma membrane becomes dimpled, or caved in at points. These pits separate from the surface and form pinocyotic vesicles.
Pinocyotic Vesicles
a vesicle in the cytoplasm that forms via pinocytosis
Receptor Mediated Endocytosis
A more selective form of phago or pino-cytosis where receptors identify matter that the cell wants to take in. this limits the number of unnecessary matter that the cell consumes.
Semipermeable
Allows some things through but not others
Cell Membrane
Function: Controls what molecules enter and leave the cell, example: food & oxygen molecules must enter the cell AND waste product needs to be released.
Analogy: Gates/ Doors
Extracellular Fluid (ECF)
All body fluids not contained in the cells. Also called tissue or interstitial fluid
Intercellular Fluid
Fluid within the cell that surrounds the cytoskeleton, organelles, and inclusions. Also called the Cytosol.
Organelles
Internal structures within cells that carry out a specific metabolic task
Membranous Organelles
- nucleas
- mitochondria
- lysosomes
- peroxisomes
- endoplasmic reticulum
Organelles without membranes
- Ribosomes
- Proteasomes
- Centrosomes
- Centrioles
- Basal Bodies
Nucleas
Appearance: largest organelle in most cells and is surrounded by double membrane.
Function: genetic control center of cell; directs protein synthesis & shelters the DNA
Most cells contain a single nucleas.
Analogy: control center of cell/ manager’s office.
Annucleas
cells without nucleas example: red blood cells
Multinucleas
cells with multiple blood cells, example: skeltal muscle cells, liver cells, bone dissolving cells.
Nuclear Envelope
Double membrane that surrounds the nuclease
Nucleaplasm
Material in the nucleus
Chromatin
Fine threadlike matter composted of DNA and protein. Encased within the nucleaplasm
Nucleioli
Produces Ribosomes
Endoplasmic Reticulum types
- Rough E.R
2. Smooth E.R
Rough E.R
Location: extensive sheets of pparelle mebranes with ribosomes on outer surface.
Function: Protein synthesis and manufacturer of cellular membranes
Smooth E.R
Location:Branching network of tubules with smooth surface
Function: Lipid & hormone syntesis, detoxification, calcium storage
Endoplasmic Reticulum
Protein synthesis and manufacturer of cellular membranes
Analogy: Conveyer Belts
Ribosomes
Appearance/ Location:free in cytosol, on surface of rough ER and nuclear envelope, and inside nucleus & mitochondria
Function: Interpret genetic code and synthesize polypeptides
Analogy: Machines
Lysosomes
Trash disposal of cell- contains digestive enzymes that break down waste.
Package of enzymes, example: in the liver, lysosomes break down glycogen to be converted into glucose.
Analogy: Janitor
Autolysis vs Autophagy
Autolysis: the digestion of surplus cells by their own lysosomal enzymes. Some cells are meant to do a certain job and then destroy themselvesAlso known as cell suicide. Example: following pregnancy, the uterus will shrink considerably.
Autophagy: digestion and disposal of surplus or nonvital organelles in order to recycle their nutrients to more important cell needs
Golgi Complex/ Apparatus
Appearance/ location: near the nucleus, often with many golgi vesciles nearby.
Function: Delivery system of the cell- collects/ modifies/ and packages molecules into vesicles within the cell.
Analogy: post office/ mail room
Mitochondria
ATP synthesis
Analogy: power plant/ electrical room
Types of scanes
- MRI
- PET Scan
- X-Ray
MRI
Magnetic Resonance Imaging: electromagnetic scan that allows us to view inside of the body. Produces anatomical images through changes/ contrasts in alignment of hydrogen atoms with magnetic field
Example: Brain testing
Disadvantage: claustrophobia, loud noises, etc.
PET Scan
Positron Emission Tomography: used to detect the metabolic state of tissue and distinguish which tissues are most active at a given moment. Occurs through injection of radioactive glucose.
Example: examination of tissue death from a heart attack, diagnosis of cancer, examine tumor status
Disadvantage: provide low resolution
X-Ray
Example of radiography ; process of photographing internal structures with X-Rays.
Example: used in dentistry, mammography, diagnosis of fractures, and examinmation of the chest.
Disadvantage: can cause mutations leading to cancer and birth defects.
Phosopholipid Bilayer
Polar heads- hydrophilic = like water
Non polar tails- hydrophobic= fear water
Fluid Mosaic Model
Describes the various molecules found in the cell membrane; example: proteins form channels and pumps to move material across the membrane AND carbohydrates act like Identification cards so cells can identify one another.
Transport Across a Membrane
- Passive Transport:
a. difussion
b. carrier faciliated “help” difussion
c. Osmosis - Active Transport
a. Protein Pump
b. Endocytosis
c. Exocytosis
Passive Transport
- Energy is not required for movement across membrane
- Molecules move from an area of high concentration to area of low concentration
Passive Transport Factors
- Equilibrium
2. Permeability
Equilibrium
When concentrations on both sides of the membrane are equal
Permeability
Ability of a molecule to diffuse across a membrane
- Impermeable: molecules can’t move across
- Semi-Permeable: some can, others cants
Simple Diffusion
- high to low concentration
- no energy is required
- occurs because molecules constantly move and collide with eachother
Carrier- Facilitated Diffusion
- molecules helped across by carrier proteins from high to low
- no energy is required
Osmosis
-Difussion of water molecules through a selectively permeable membrane
Isotonic
- Concentration of solutes is the same in and out of cell
- equal amount of water entering/ leaving cell
Hypertonic
- Solution has a higher solute concentration than inside the cell
- More water leaves cell, causing cell to shrink
Hypotonic
- Solution has lower solute concentration than inside the cell
- More water enters cell, causing cell to expand
Active Transport
- Energy ie ATP is required for molecules to pass across membreane
- ATP= battery of cell and breaking a bond in ATP releases energy
- can pump molecules from lowe to high concentration
Protein Pump
- Example of active transport
- Protein pumps pull molecules through
- ATP is required
Organic Compounds
Contain Carbon
Organelle
“Little Organs”
Specialized structures that perform specific jobs in a cell.
Macromolecules
Large organic molecules, also called polymers
Macromolecule examples
- Carbohydrates
- Lipids
- Proteins
- Nucleic Acids (DNA & RNA)
Dehyrdration Synthesis
Macromolecule/ Polymer formation through monomers combining via removal of water. Also called condensation reaction.
Hydrolysis
Macromolecule seperated/ digested by adding water. Formation of monomers
Carbohydrate Types
- monosaccharide
- disaccharide
- polysaccharide
Monosaccharide
One sugar unit; example: glucose, deoxyribose, ribose, fructose, galactose
Disaccharide
Two sugar unit, example: sucrose (glucose+fructose), lactose (glucose + galactose), maltose (glucose+glucose_
Polysaccharide
Many sugar units; Example: starch (bread, potatoes), glycogen (beef muscle), celluose (lettuce/ corn)
Lipids
- General term for compounds not soluble in water
- Lipids are hydrophobic solvents
- stores the most energy
Lipid Examples
- Fats
- Phopholipids
- Oils
- Waxes
- Steroid Hormones
- Triglycerides
Lipid Functions
- Long term energy storage
- Insulation
- Protection against physical shock
- protection against water loss
- chemical messengers (Hormones)
- Major component of membranes (phospholipids)
Triglyerceride
1 glyercol + 3 fatty acids
Fatty Acids, two types
- saturated fatty acid- no double bonds
2. unsatuarated fatty acid- double bonds- has a kink
Proteins
Polypeptides; bonded by peptide bonds
Protein Funcitons
- Storage
- Transport:
- Regulatory: hormones
- Movement: muscles
- Structural: membranes, hair, nails
- Enzymes; cellular reactions
Types of protein structures
- primary- linear chains bonded by peptide bonds
- secondary- 3 dimensional folding arrangement into coils & pleats held together by hydrogen bonds
- tertiary - secondary structures bent and folded into more complex 3D arrangements; bonded by hydrogen, ionic, and disulfide bridges ; called sub-unit
- quaternary - composed of two or more sub-units; globular in shape and form in acqeuous solutions. example: enzymes
Nucleic Acids
long chains of nucleotides linked by dehydration synthesis
Nucleic Acids Types
- DNA- double helix
2. RNA- single strand
Mitosis Phases
PMAT:
- Prophase
- Metaphase
- Anaphase
- Telophase
- Cytokinesis
Diploid Cell
has pairs of chromosomes ie: 46 chromosomes
Prophase
- chromosomes condense and nuclear envelope breaks down
- centrioles will replicate (forms two pairs) and move to opposite sides
- start to form spindles (made of microtubules)
Metaphase
-chromosomes line up along equator
Anaphase:
-chromosomes split and start moving across opposite poles
Telophase
chromosomes gather at each pole of cell- new nuclear envelope appears at each pole- new nuclei appear - mitotic
cytokinesis
-cytoplasm splitting apart to form two new cells
Cytosol vs Cytoplasm
Cytoplasm= everything contained within a cell Cytosol= fluid/ matrix of the cytoplasm
Interphase
G1= Growth and Normal Metabolic Roles
S= Synthesis/ DNA Replication
G2=Second gap phase; Growth & Preparation for mitosis
M=Mitotic Phase - splitting of duplicated cells