Lecture 7 - Cells Flashcards
Cell
Fundamental unit of life
Three domains of cells:
Bacteria, Archaea, Eukarya
Two types of cells:
Prokaryotic Cells (includes domains bacteria and archaea)
Eukaryotic Cells (includes domain eukarya)
Some properties of Prokaryotic cells:
small
simple
no nucleus
no organelles
Some properties of Eukaryotic cells:
large
complex
has nucleus
has organelles
Components of Eukaryotic Cells:
Plasma membrane
Cytoplasm
Ribosomes
Nucleus
Endomembrane system
Organelles
Cytoskeleton
Extensions
2 main types of eukaryotic cells:
Plant cells
Animal cells
Components special to plant cells:
Cell wall
Vacuole
Chloroplast
Component special to animal cells:
Centriole
The plasma membrane (animal cells):
Hydrophobic barrier to the external environment, formed by phospholipid bi-layer in which there are embedded proteins
also has some cholesterol which acts as a stabilizer
The fluidity of membranes is determined by:
Phospholipid movement
Saturated vs unsaturated hydrocarbons
Cholesterol presence
Functions of plasma membrane proteins:
Support
Cell-cell recognition
junctions
enzymatic
receiving and transmitting messages from the receptors
transport
cytoplasm:
cytosol and all organelles within a cell
Is cytoplasm present in either animal or plant cells?
present in both
Ribosomes
Play a key role in protein making process
2 Types of Eukaryotic Ribosomes:
Rough ER associated ribosomes
Free ribosomes
Rough ER associated ribosomes:
Assist in making plasma membrane and proteins that are to be sent out of the cell
Free ribosomes:
Assist in making proteins that will reside in cytoplasm
Nucleus
Control center
What does nucleus contain?
DNA & RNA
Nuclear envelope
Nucleus is covered by nuclear envelope.
Nuclear envelope is made of 2 membranes:
Inner membrane, outer membrane
Eukaryotic DNA contains small proteins called_________, forming _________.
Histones, Chromatin
With aid of other proteins, chromatin condenses to form:
Chromosomes
Define Nucleolus:
Dense region in the nucleus where ribosomes are assembled
Endomembrane system consists of:
Rough endoplasmic reticulum, smooth endoplasmic reticulum, golgi apparatus
Define translation process in rough ER:
Ribosomes in rough ER are called membrane bound, and are responsible for the assembly of many proteins
Proteins staying in the cytoplasm are made on:
Free ribosomes
Smooth endoplasmic reticulum:
Large, dynamic structure that serves many roles including calcium storage, protein synthesis, and lipid metabolism
The golgi apparatus:
Major site of carbohydrate synthesis, as well as sorting and dispatching station for the products of ER
Lysosomes
Involved in digestion and waste removal
Mitochondria
Harvest chemical energy from food, store energy (ATP), cellular respiration
Mitochondria has how many membranes?
two membranes: inner, outer
Vacuoles Function
Store water, salts, proteins, and carbs
Vesicles Function
Store and move materials between organelles
Cytoskeleton Functions
Structural support, movement of organelles, cell locomotion
What fibers are cytoskeletons made of?
Microtubule, intermediate filament, microfilament
Microfilament properties:
Thinnest
Subunit: Actin
Cell shape
Cell movements
Intermediate Filaments Properties:
In-between size
Fibrous proteins
reinforce cell shape
anchor organelles
Microtubules Properties:
Hollow tubes
tubulin proteins
easily put together and taken apart
cell shape
What are the two cell extensions found in eukaryotic cells?
Flagella & Cilia
Flagella are:
Long, one or few
Cilia are:
Short and many
How does a flagellum move?
Propeller-like motion
How do cilia move?
Back and forth beating
Centriole Definition:
Microtubule organizing centers
These microtubules separate chromosomes
What are three types of connections between animal cells?
Tight Junctions
Anchoring Junctions
Communicating Junctions
Tight Junctions properties:
Form continuous seals
Leak-proof
Prevent infection
Anchoring Junctions properties:
Rivet Cells together
Very Strong
leaky
Communicating Junctions properties:
Channels link neighbors
Let small molecules & ions move from cell to cell
How long prokaryotes have been present?
3.5 billion years
What type of environments prokaryotes are present in?
all types of enironment - moderate to extreme
What are prokaryotic cells made of?
DNA
Plasma Membrane
Ribosomes
Cell Wall
Pili
Flagella
Capule
Define Plasmids
Circular, double-stranded units of DNA that replicates within a cell
Prokaryotic plasma membranes are made of:
Lipids, specifically phospholipids
The prokaryotic cell wall is made of:
Peptidoglycan - complex interlocking of polymers of nitrogen-sugar monomers
Cell wall of prokaryotes surrounds the:
bi-lipid, plasma membrane layer
The prokaryotic cell wall prevents the_____:
Rupturing of the bacterium by osmotic pressure of water
Define Pili:
Thin, rigid fiber made of protein that protrudes from the cell surface
Pili function:
To attach a bacterial cell to specific surfaces for plasmid transfer
Define flagellum:
Rotates like a propeller and allows movement of the bacteria through the environment in response to it