Introduction to Cells Flashcards
What organelles do ALL cell types have?
Cell membrane, DNA, cytoplasm and ribosomes
Describe prokaryotic cells
Small, simple internal structure with no membrane bound structure or organelles, includes bacteria, no nucleus
Describe eukaryotic cells
Larger, complex, found in higher-order animal and plants, has a nucleus
What is the cell plasma membrane?
A semi-permeable barrier between cytoplasm and external environment
What is the function of the cell membrane?
Retains organically produced chemicals, allows a few molecules across e.g. oxygen and glucose by diffusion/osmosis/active transport/facilitated diffusion, communication by receptors on cell surface
Describe the structure of the plasma membrane
Fluid Mosaic. Phospholipid’s have a hydrophilic head and hydrophobic tails. Cholesterol is embedded in the bi-layer and provides membrane integrity. Proteins are gateways allowing certain molecules into and out of the cell
Describe a cell membrane pathology
Sickle cell anaemia. Hereditary, haemoglobin defects, alterations in lipid bi-layer phospholipids decrease red blood cells life span
What happens in the nucleus?
Location of most different types of amino acids, DNA restricted to the nucleus, RNA synthesised here (site of transcription)
What is the nuclear envelope?
Double-membrane structure allowing RNA and other chemicals to pass but not DNA.
What is the nucleolus?
The area where ribosomes are made
What is the main function of ribosomes?
Facilitate protein translation
Describe the sites of the ribosome
E = exit site, P = peptidyl-tRNA binding site, A = aminoacyl tRNA binding site
Describe a ribosome pathology
Treacher Collin’s Syndrome - abnormal craniofacial development
Describe the endoplasmic reticulum
Mesh of interconnected membranes, involved in protein synthesis and transport
What is the function of the rough ER?
Protein modification and production
What proteins does the rough ER produce?
Lysosomal enzymes, secreted proteins, integral membrane proteins
What is the function of the smooth ER?
Detoxifies organic chemicals and converts them into water soluble products.
What does ER dysfunction result in?
Defective folding and processing of proteins. Plays a role with neuro-degenerative diseases and associated with ageing.
What goes into the Golgi apparatus?
Only correctly folded proteins go to the Golgi apparatus via transport vesicles.
What is the function of the Golgi apparatus?
Further modifies proteins, stores proteins, packages proteins.
What is a Golgi-related disease?
Muscular dystrophy. Functionality lost due to mutations in proteins that make up the Golgi.
Describe vacuoles
Single-membrane organelles, storage areas, formed by fusion of numerous vesicles
Describe vesicles
Smaller than vacuoles, function in transport within and to the outside of the cell
Describe lysosomes
Large vesicles formed by Golgi apparatus, contains hydrolytic enzymes capable of destroying the cell, contents function in the breakdown of extracellular material.
What do vacuoles, vesicles and lysosomes all make up?
The endomembrane system
What is the function of the mitochondria?
Site of energy release and ATP formation.
Describe the outer membrane of the mitochondria
Smooth and sieve like
Describe the inner membrane of the mitochondria
Folded into cristae surfaces on which ATP is generated
What are mitochondrial dysfunctions
Mutations in the maternal DNA of the mitochondria
What is the cytoplasm?
Material between the cell membrane and the nuclear envelope
What is the function of the cytoplasm?
Facilitates transport of material around the cell
What is the cytoskeleton?
Fibrous proteins in the cytoplasm
What is the function of the cytoskeleton?
Maintains shape of the cell, anchors organelles, moves cell, controls internal movement of organelles.
