Ch.6 (Cell Structure and Function) Flashcards
Cell Theory - Biogenesis (3)
All living things are composed of one or more cells.
Cell is the smallest unit of life.
Cells can only be made from pre-existing cells.
Purpose of cell division (2)
Reproduction, growth and repair in multicellular organisms
Types of cells (2)
Prokaryote, Eukaryote
Prokaryotes (2)
Bacteria, archaebacteria & smaller
Eukaryotes (2)
Protists, fungi, plants, animals & larger
Virus
Considered non-living because it cannot reproduce without host cell
Virus Prop.1
Contains DNA or RNA
Virus Prop.2
Contained within protein shell called CAPSID
Capsid
Protein shell in which the virus is contained
Virus Prop.3
Capsids of some viruses are surrounded by additional membranous envelope derived from host cell
Cell size (give a number)
1-100 um
Microscopes used to observe cells (2)
Light, electronic
Light microscope
Visible light optics (lenses), limited resolution & magnification
Electronic microscope
electron optics (magnets), high resolution & magnification
Resolution
amount of detail visible ; minimal distance at which two points are seen distinctly
Magnification
ratio of image size over object size
Limits to cell size : Upper
surface to volume ratio
Limits to cell size: Lower
lack of space to contain all molecules to sustain life
What happens if a cell is very large?
Surface of PM may not be large enough to allow exchange of the cell with environment
Solutions to Upper Limit (2)
Compartments
Adopt elongated shapes (microvilli)
Minimal cell components (4)
Cell Membrane = plasma membrane PM
DNA
Cytoplasm (H2O)
Ribosomes (protein synthesis)
Plasma Membrane (PM) (3)
maintains the cell as a distinct entity
phospholipid bilayer + proteins + cholesterol (for animal)
semi-permeable
PM permeability (what is permeable and what is not?)
impermeable to hydrophilic substances (ions, polar water molecules, sugars)
permeable to hydrophobic, non-polar substances (gas, lipid soluble molecules, cholesterol)
membrane transport proteins - what do they do?
allows passage of hydrophilic substances
Prokaryotic Cell (8)
bacteria
no nucleus
no membrane bound cytoplasmic organelles (nucleus, mitochondria, Golgi, etc.)
nucleoid
cell wall: peptidoglycan
capsule
pili
flagella
Peptidoglycan
Cell wall of prokaryotic cells
Capsule
Polysaccharide for attachment in some prokaryotic cells
Pili
extensions for attachment in some prokaryotic cells
Flagella
for locomotion in some prokaryotic cells
Nucleoid
in prokaryotic cells ; similar to the nucleus - area for DNA
*DNA in single circular chromosome
Organelles (2)
compartments or structures inside cell with specific function
generally membrane bound but can be without
Organelles of Eukaryotes (3)
nucleus, endomembrane system, (system includes several), peroxisomes
Eukaryote Organelle - Nucleus (4)
enveloped by double membrane (2 bilayers)
contains genetic info
site of transcription and replication
contains nucleolus
Nuclear Envelope (2)
double membrane of the nucleus in eukaryotic cells
consists of pores which allow passage of molecules
Nucleolus (3)
denser structure within nucleus of eukaryotic cell
site of rRNA synthesis
ribosome assembly
RER - Endomembrane System of Eukaryotic cell (4)
Rough Endoplasmic Reticulum
attached-bound ribosomes
protein synthesis of secreted and membrane proteins
glycoproteins (blood antigens) modified in RER
SER- Endomembrane System of Eukaryotic cell (5)
Smooth Endoplasmic Reticulum
no ribosomes
lipid biosynthesis
site of detoxification of drugs & natural waste (liver)
storage of muscle fibres
Lipid Biosynthesis - SER
phospolipids
steroid hormones : ovaries and testis
cholesterol : liver
Golgi - Endomembrane System of Eukaryotic cell (2)
protein folding
protein modification
“ZIP code”
Lysosomes- Endomembrane System of Eukaryotic cell (4)
ANIMAL ONLY
hydrolytic enzymes: macromolecule digestion
large food particules (phagocytosis)
damaged organelles (autophagy)
“stomach of the cell”
Central Vacuole- Endomembrane System of Eukaryotic cell (3)
PLANT ONLY
multiple functions:
-storage of waste
-water homeostasis
What organelles have roles in metabolism?
Mitochondria
Chloroplast
Role of mitochondria in metabolism (2)
cellular metabolism
production of ATP
Role of chloroplast in metabolism
photosynthesis
Endosymbiont theory
organelles originate from bacteria
Peroxisomes (3)
site of detox of oxygen radicals
detox alcohol in liver cells
fatty acid catabolism
Cell Shape components (2)
cell wall (not for animals)
cytoskeleton
Cell Wall for Plants
Cellulose
Cell Wall for Fungi
chitin
Cell wall for bacteria
peptidoglycan
Cytoskeleton (3)
maintains cell shape and anchors organelles for EUKARYOTIC cells
dynamic role in cellular division, protein transport and cell movement
constituted of filaments
Which type of cell does NOT have a cytoskeleton?
Bacteria
What are filaments in cytoskeletons made of?
Protein
Types of filaments (3)
Microfilaments
Intermediate filaments
Microtubules
(2) Microfilaments
also called Actin Filaments
associated with PM
Functions of Microfilaments (4)
shape: microvilli
motility
muscle contraction : actin-myosin in sarcomere
cell division : actomyosin ring during cytokinesis
Functions of Intermediate Filaments (3)
strength and shape of cells
anchors organelles
forms nuclear lamina
Nuclear Lamina
cage-like structure in nuclear envelope
Microtubules (MT) (2)
made of tubular protein dimers
grow at centrosomes, microtubule organizing centres (MTO) and basal bodies (flagella, cilia)
Functions of Microtubules (3)
Cell shape and cell movement (cilia and flagella –> 9+2 arrangement)
cell division (chromosome movement): mitotic spindle
organelle movement: tracks for transport of vesicles during protein secretion
9+2 arrangement
for microtubules in cell ; 9 pairs and 2 singles)
What functions of some filaments require energy (ATP hydrolysis)? (6)
Microfilaments (3):
-motility
-muscle contraction
-cell division
Microtubules (3):
-cell movement
-cell division
-organelle movement
