Lecture 6: INTRO Cell structure and function Flashcards
What is cell theory?
- All living organisms are composed of one or more cells
- The cell is the basic unit of structure and organisation
- All cells arise from pre existing cells (via mitosis or meiosis)
What are the common features of prokaryotes and eukaryotes?
Both have cell surface plasma membrane
Have ribosomes
Have cytosol
Have DNA, RNA and protein
What are the differences between prokaryotes and eukaryotes
Eukaryotes have membrane bound organelles and are larger
Prokaryotes have no membrane bound organelles and are smaller
What is cytoplasm?
Everything inside the plasma membrane including the organelles, but not including the nucleus
What is cytosol?
The fluid in the cytoplasm - composed of water and dissolved substances (ions, ATP, proteins, lipids)
What is the endomembrane system?
The organelles of a cell involved in packaging, labelling, and shipping molecules around the cell
Made up of: Nucleus ER smooth and rough Golgi apparatus Lysosomes
Plasma membrane function
The plasma membrane is a selectively permeable barrier controlling the passage of substances in and out of the cell
Plasma membrane structure
Double layer of phospholipids with embedded proteins
Phospholipid structure
Made up of a hydrophilic phosphate head and two hydrophobic fatty acid tails arranged as a tail to tail bilayer
What are integral proteins
proteins embedded partially or fully in the plasma membrane
What are transmembrane proteins
Type of integral protein that spans the whole membrane coming in contact with extracellular and cytoplasmic areas
What are peripheral membrane proteins
Associated with the membrane but not embedded in them
What is function of peripheral membrane proteins
Cell to cell identification and facilitate intercellular communication
What is function of integral proteins
Mediate movement of hydrophilic substances
What are 6 functions of plasma membrane proteins?
Transport Enzymatic activity Signal transduction Cell-cell recognition Intracellular joining Attachment to cytoskeleton and extracellular matrix
Nucleus function
House DNA in eukaryotic cells
Make RNA and assemble ribosomes
pores regulate movement of substances (protein and mRNA) in and out
molecule segregation to allow temporal and spatial control of cell function
Nucleus structure
The largest distinct structure in the cell Made up of: nucleolus nuclear envelope nuclear pores
What is nucleolus
Dark region of nucleus where rRNA are produced later forming ribosomes
What is nuclear pores?
Gaps in the nuclear envelope controlling exit and entry into nucleus
What is nuclear envelope
Membrane surrounding nucleus
What is DNA
Deoxyribonucleic acid - encodes our phenotype