Lecture 2a-e: Cell Structure and Function Flashcards
Structures common to all living cells?
- Plasma membrane
- Cytoplasm
- Chromosomes
- Ribosomes
- Cytoskeleton
Plasma Membrane
A bilayer made of phosolipid molecules with embedded protein molecules
Semi-permeable membrane
Controls the flow of substances into and out of a cell
The lipid bilayer is a _________ ________ to water soluble substances
Hydrophobic barrier (selected ubstances can penetrate cell membranes through transport protein channels)
Cytoplasm
Describes all material within a eukaryotic cell (between the plasma membrane and the central region)
The Central Region
Contains DNA molecules, which contain hereditory info (genes)
Cytosol
The aqueous portion of the cytoplasm in an intact cell (contains H2O, dissolved ions and various organic molecules
Cytoskeleton
Maintains cell shape and plays key roles in cell division and chromosome segregation
Which cells are prokayotic?
Bacteria and Archea
Which cells are eukaryotic?
Animals, plants, fungi, and protists
3 most common shappes among prokaryotes:
Spherical, rodlike, and spiral
Glycocalyx
A rigid external cell wall coated with polysaccharides
Slime Layer
When the glycocalyx is loosely associated with the cells
Capsule
When the glycocalyx is firmly attached with the cells
Flagella
Long tail-like structure that helps may bacteria and archeans move around
Pili
Hair-like structures that attach the cell to surfaces or other cells
Organelles in animal cells, but not plant cells:
- Lysosomes
- Centrioles
- Flagella (in some plant sperm)
Organelles in plant cells, but not animal cells:
- Chloroplasts
- Central vacuole and tonoplast
- Cell wall
- Plasmodesmata
Eukaryotic Cell: Nuclear envelope
Is made up of 2 lipid bilayer membranes that in eukaryotic cells surround the nucleus
Eukaryotic Cell: Nuclear pore
Is a protein-lined channel in the nuclear envelope that regulates the transportation of molecules between the nucleus and the cytoplasm
Eukaryotic Cell: Nucleolus
Is the distinct structure present in the nucleus of eukaryotic cells (it mainly participates in the assembliing of the ribosomes)
Eukaryotic Cell: Chromatin
Is a complex of DNA and proteins that forms chromosomes within the nucleus of eukaryotic cells
Eukaryotic Cell: Nuclear Lamina
is a dense fibrillar network of intermediate filaments and membrane associated proteins located in the inner nuclear membrane
What structures are in the nucleus of a eukaryotic cell?
- Nuclear envelope
- Nuclear pore
- Nucleolus
- Chromatin
- Nuclear lamin
What are ribosomes comprised of?
Each ribosome is composed of 2 subunits, a large subunit and a small subunit
Ribosomes serves as the site of _______ _______ via decoding the message and formation of peptide bonds
Protein Synthesis
Components of the Endomembrane system:
- Nuclear envelope
- Endoplasmic reticulum
- Golgi apparatus
- Lysosomes
- Vacuoles
- Plasma membrane
2 Types of ER:
Smooth ER (lacks ribosomes) and Rough ER (has ribosomes)
Functions of the rough ER
- Has bound ribosomes
- involved in modification and folding of proteins
- Manufactures membranes by producing membrane proteins and phosolipid molecules
- Is a membrane factory
Function of the Smooth ER:
- Synthesises lipids
- Regulates carbohydrate metabolism in some cells
- Stores calcium
- Detoxifies toxins and drugs
Functions of the Golgi apparatus:
- Modifies products of the ER
- Manufactures certain macromolecules
- Sorts and packages materials into transport vesicles
Lysosome
A membranous sac of hydrolytic enzymes (can hydrolyze polysaccharides, and nucleic acids)
Phagocytosis
Is the cellular process by which a cell uses its PM to engulf a large particle, giving rise to an internal compartment (Phagosome)
Autophagy
The concerved degradation of the cell that removes unnecessary or dysfunctional components through a lysosome-dependant regulated mechanism
Vesicle
A structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a membrane layer
How are food vacuoles formed?
Phagocytosis
Mitochondria are the sites of ________ _________?
Cellular Respiration
Chloroplasts (found in plants and algae) are the sites of _________?
Photosynthesis
Peroxisomes
Are oxidative organelles
The inner membrane in the mitochondria creates which 2 compartments?:
Intermembrane space and mitochondrial matrix
Choloplast structure includes:
- Outer and inner membrane
- Thylakoids
- Thylakoid membranous sacs
- Stroma, the internal fliud
Peroxisomes
Specialized metabolic compartments bounded by a single membrane (they produce hydrogen peroxide)
3 Structures that the cytoskeleton is composed of:
Microtubules
Microfilaments
Intermediate FIlaments
Roles of the Cytoskeleton
- helps support the cell and maintain its shape
- Produce motility
- help regulate biochemical activities
Functions of Microtubules:
- shaping the cell
- guiding movement of organelles
- separating chromosomes during cell division
- Making up the internal structure of cilia and flagella
Centrosome
“microtubule-organising center”
The centrosome has a pair of centrioles, each with 9 triplets of microtubules arranged in a ring
Cilia
A membrane-bound organelle found on most parts of eukaryotic cell; it has he sape of a slender threadlike projection that extends from the surface of the much larger cell body
Flagella
Found on sperm cells of eukaryotes and many protozoans have a similar structure to motile cilia that enables swimming through liquids
Functions of Microfilaments:
- Actin works with another protein called myosin to regulate muscl movements, cell divison, cell tension, cytoplasmic streaming, etc
- Support the cell’s shape and keep organelles in place
Extracellular Components (Structures) and Connections between cells:
- Cell walls of plants
- The extracellular matrix (ECM) of animal cells
- Intercellular juctions
Plant cell walls may have multiple layers such as:
- Primary Cell wall: relatively thin and flexible
- Middle lamella: Thin layer between primary walls of adjacent cells
- Secondary cell wall ( in some cells): added between the plasma membrane and the primary cell call
The Extracellular Matrix (ECM)
It is made up of gycoproteins and other macromolecules
Functions of the Extracellular Matrix (ECM):
- Support
- Adhesion
- Movement
- Regulation
Intercellular Juctions
Neighboring cells in tissues, organs, or organ systems often adhere, interact, and communicate through direct physical contact
plasmodesmata arre junctions between plant cells, whereas animal cell contacts include tght junctions, gap junctions, and desmosomes
Plasmodesmata (PD)
Are membrane-lined pores that connect adjacent cells to mediate symplastic communication in plants (facilitate transport of small mmolecules)
Tight Junctions
Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid
Desmosomes (anchoring juctions)
Fasten cells together into strong sheets
Gap Juctions (communicating Junctions)
Provide cytoplasmic channels
