Anatomy of the cell Flashcards
What type of cell has a high water content
Embryonic
What type of cell has a low water content
Old
What are the materials found in a cell
Water
Protein
Lipid
Carbohydrate
Inorganic
What are the features of a eukaryotic cell
Outer membrane
Inner cytosol
Cytoskeleton
Membrane bound organelles
Inclusions
What is cytosol
Solution of proteins, electrolytes and carbohydrates. Has both fluid and gel-like properties
What is the function of the cytoskeleton
Determine the shape and fluidity of the cell
What are the components of the cytoskeleton
Thin filaments, intermediate filaments, microtubules
What is the function of the plasma membrane
Separates the cytoplasm from the outside environment
What are the components of the plasma membrane
Hydrophilic heads at the outer and inner surfaces and hydrophobic fatty chains facing the middle.
What examples of integral proteins
receptors,
channels,
transporters,
enzymes
cell attachment proteins
Define exocytose
Takes materials from inside the cell and pulls them to out of the cell
Define endocytose
Pulls materials from outside the cell to inside the cell
What are membrane proteins
Can diffuse laterally in the cell membrane. Many are anchored, not equally distributed along the cell membrane
Which term best describes the cell membrane
Selectively permeable
What is the cell membrane highly permeable to
Water
Oxygen
Small hydrophobic molecules
What is the cell membrane virtually impermeable to
Charged ions (Na+)
What are organelles
Small intracellular organs with a specific function and structural organisation
What is the function of the mitochondria
Generate ATP via oxidative phosphorylation. Involved in the synthesis of certain lipids and proteins
What are the key components in the structure of the mitochondria
Outer and inner membrane
Inner membrane folded to form cristae which increases surface area
Contains own DNA for protein production
What is the function of the rough endoplasmic reticulum
Protein synthesis and initiation of glycoprotein formation
What is the function of the smooth endoplasmic reticulum
Cholesterol and lipid synthesis/detoxification
What is the function of the Golgi apparatus
Modification and packaging of secretions (macromolecules).
What are some modifications that take place in the golgi apparatus
Add sugars
Cleaves some proteins
Sorts macromolecules into vesicles
What are lysosomes
Membrane bound organelles containing hydrolytic enzymes for intracellular digestion
What are cell inclusions
Not always membrane bound.
Dispensable and not always present (transient).
What are examples of some inclusions
Pigment
Glycogen stores
Lipid droplets
Presecretion product
What are microfilaments composed of
Fine strands of the protein actin
How do actin molecules function
By assembling into filaments and disassembling. Very dynamic
What are intermediate filaments composed of
6 main proteins which vary in different cell types. Many different types exist and are used to identify tumour origin
What are microtubules composed of
2 tubulin proteins which attach to the cell membrane and each other
What is the function of intermediate filament
Bind intracellular elements together and to the plasma membrane. Form a network throughout the cytoplasm
What are the components of a microtubule
Hollow tubule, 2 types of subunits - alpha and beta.
What is the function of the microtubule organising centre
Centromere where microtubules associate from. Includes stabilising proteins known as microtubules associated proteins (MAPS)
What are 2 types of motor proteins
Dynein
Kinesin
What is the function of microtubules
Important in the mitotic spindle. Serve as a motorway network for proteins.
What is the function of kinesin
ATPase that moves toward the cell periphery (edge)
What is the function of dynein
ATPase that moves towards the cell centre
What is the structure of the nucleus
Nuclear envelope
Chromosomes
Nucleolus
What is the function of the nucleus
Contains genetic code. Site of transcription for mRNA and tRNA
What is transcribed in the nucleolus
rRNA
What is heterochromatin DNA
Highly condensed
not undergoing transcription
What is DNA in euchromatin
dispersed
actively undergoing transcription
What are the types of DNA in the nucleus
Euchromatin
Heterochromatin
What are the main components in the structure of the ribosome
Made up of a small subunit which binds RNA.
Made up of a large subunit which catalyses the formation of peptide bonds
What does the export of ribosomes depend on
the nuclear core complex
Why are ribosomes important
Required for protein synthesis.
What is the endoplasmic reticulum
Forms a network of interconnecting membrane-bound compartments in the cell.
When does a cell have more endoplasmic reticulum
When it is more metabolically active
What is the function of an intercellular junction
Link individual cells together via a specialised membrane structure
What is an occluding junction
Link cells to prevent diffusion. They tie membranes together
What is an anchoring junction
link submembrane actin bundles.
They do not connect directly
What is a communicating junction (gap junction)
Allow selective diffusion of molecules dependant on molecular size.
Communicating junctions contain pores
What are Desosomes
Link actin bundles in anchoring junctions
Where are communicating junctions found
epithelia
smooth muscle
cardiac muscle where it is used for the spread of excitation
What is a junctional complex
Close association of several types of junctions found in certain epithelial tissues
What are the types of vesicular transport from outside the cell to inside
Endocytosis
Phagocytosis
What are the types of material transport between cell membranes
Diffusion
Transport via proteins (pump or channel)
Vesicular transport
What is endocytosis
Cell membrane invaginates then fuses
Endocytotic vesicle buds into cell (receptor needed)
What is phagocytosis
Bacterium binds to surface receptor which activates trigger
its then engulfed forming a phagosome. Phagosome binds to lysosome forming phagolysosome
When does phagocytosis occur
when transporting larger material or bacteria
