Week 4: The cell Flashcards
What are the two types of cells?
Prokaryote
Eukaryote
What do prokaryotae cells lack?
A distinct membrane bounded by a membrane
Membrane-bound organelles such as mitochondira and chloroplasts
What are the features of DNA within prokaryotic cells?
Single circular and some small
What is the DNA in prokaryotic cells called and where is it?
Plasmids in the cytoplasm
What are the features of the nucleus in eukaryotic cells?
Have a true nucleus that is separated form cytoplasm by a nuclear envelope
What do eukaryotic cells contain for respiration?
Mitochondria
What does the nucleus contain?
DNA
Condensed and organised with proteins as chromatin
What is the nucleus surrounded by?
Nuclear envelope on the exterior
How many nuclear pores does the nucleus contain and what are they regulated by?
Roughly 3000
Protein structures
What is a nucleolus and when does it become enlarged?
A spherical body of the nucleus of most eukaryotes that becomes enlarged during protein synthesis
What does the nucleolus contain?
DNA templates for ribosomal RNA
Is the genetic code (DNA) of all cell in the body identical?
Yes
How many genes do humans have?
25,000
What is the most diverse and complex macromolecules in cells?
Protein
What is gene encode for proteins used for?
Structure
Function
Information
How are gene encode for proteins made up?
Linearly arranged amino acid residues
How much energy does mitochondria contribute to cellular energy?
80%
Do mitochondria have their own DNA?
Yes
How many genes does mitochondria encode?
37
What does the endoplasmic reticulum form?
Interconnected network of tubules, vesicles and cisternae within cells
What is the endoplasmic retuculum a site of?
Protein synthesis and packaging of cell chemicals into transport vesicles
What is the difference between rough and smooth endoplasmic reticulum?
Rough ER is smooth ER with ribosomes
What are ribosomes made of?
Protein and rRNA
What is golgi apparatus?
Stacks of membrane-bounded sisternae located between the ER and cell surface
What are peroxisomes?
Membrane bound enzyme sacs
What do peroxisomes do?
Various energy substrates are broken down by oxidative reactions in peroxisomes
What is the cytosol?
Where all chemical reactions occur
What is the function of the cytoskeleton?
Providing mechanical strength Locomotion, remodelling Chromosome separation in mitosis and meiosis Intracellular transport of organelles Cellular signalling
What is endocytosis?
Cell membrane invaginates, pinches in, creates vesicle enclosing contents
What is exocytosis?
Membrane vesicle fuses with cell membrane, releases enclosed material to extracellular space
What is the extracellular matrix?
Proteins exocytosed in to the extracellular space
How permeable is the membrane?
Selectively membrane
What are the passive forms of transport that can cross the membrane?
Simple diffusion
Facilitated diffusion
Osmosis
What are the active forms of transport that can cross the membrane?
Pumps
Carriers
What does osmosis refer to?
The diffusion of water across a membrane that is semi-permeable
What way will water does water move in different concentrations?
Water moves from an area of low solute conc to an area of high solute conc
What is facilitated diffusion?
Solute molecules bind with channel protein to pass across the membrane
What is the carrier molecule made of?
Integral membrane proteins
