Cell Structure, Evolution and Protein Sorting Flashcards
What is a cell?
The basic unit of life
Name the 4 types of tissues
Muscle
Epithelial
Nervous
Connective
What are the 5 Organisation levels?
Cell
Tissues
Organ
Organ System
Organism
How do we know something is alive?
Living things are made of cells. Something is alive if the following things take place:
Respiration
Movement
Nutrition
Growth
Reproduction
Sensitivity
Excretion
Explain the Schleiden and Schwann Cell Theory
The cell is the fundamental unit of structure and function in living things
All organism are made up of one or more cells
Cells arise from other cells through cellular division
Explain the Endosymbiotic Theory for Animals
Plasma membrane starts to folds and endomembrane components start to form including the nucleus and endoplasmic reticulum
Ancestral eukaryote consumed aerobic bacteria that evolved into mitochondria
How is the endosymbiotic theory different for plants?
They have an extra stage
Early eukaryotes consumed photosynthesis bacteria that evolved into chloroplast.
What are the 3 domains of life?
Bacteria
Archaea
Eukaryote
What domain do prokaryotes belong to?
Archaea or bacteria
What domain do Eukaryotes belong to?
Eukaryote
Explain what Archaea are and give names of environments where you can find them
Extremophiles that live in extreme environments like bigs, salt lakes and volcanoes
Explain the different types of bacteria are
E.coli found in intestine
Cyanobacteria - role in ecology and evolution
Explain what viruses are
Viruses are smaller than bacteria and contain a simple structure.
Explain the structure of viruses
Nucleic acid genome
Protein capsid - protects genetic material
Lipid Envelope - Some e.g influenza
Are viruses alive?
They are not alive as they cannot reproduce by themselves and they also cannot carry out metabolic reactions
Explain the 3 types of structure of Prokaryotes, give examples
Rods, Balls and Helices
Examples: E.coli, Streptococcus, Enterococcus
Filamentous
Examples: Helicobacter pylori, Cyanobacteria
What are Gram-negative bacteria and give examples
Bacteria that’s are resistant to antibiotics.
Examples: E.coli, Pseudomonas
What colour and shape under a microscope are gram-negative bacteria?
Pink either ball or rod shape
What colour and shape under a microscope are gram-positive bacteria?
Purple either ball or rod shape
What are gram-positive bacteria and give examples
Bacteria that contain thick cell walls . When gram testing is carried out the cell wall becomes purple
Examples: Streptococcus, Bacillus
Steps to carry out Gram Staining
Apply a crystal violet dye - purple in colour
Add iodine to form complex
Wash with Alcohol
Apply safranin
Gram-positive = Purple
Gram-negative = Pink
Explain the difference in structure between prokaryotic and eukaryotic cells
Eukaryotic cells contain a nucleus which cantinas genetic material in the form of chromosomes
Prokaryotic cells contain no nucleus, their genetic material is contained within circular pieces of DNA
Prokaryotic cell contain a cell wall made out of peptidoglycan
Eukaryotic cells contain membrane bound organelles e.g. Mitochondria, Endoplasmic reticulum, ribosomes, Golgi. Plant cells have chloroplasts
What is the function of the nucleus?
Site of ribosomal RNA synthesis contain all the genetic information of the body.
Role of Endoplasmic Reticulum
Lipid Synthesis
Detoxification (liver)
Calcium Storage (muscle)
Role of Rough Endoplasmic Reticulum
Synthesis of proteins which are secreted from the cell and the incorporated into the plasma membrane and transported to a different organelle where protein modification can take place (e.g. making a glycoprotein)
Role of the Golgi Apparatus
Further Procession of secreted proteins and sorting proteins into vesicles, lysosomes formation and vesicles are transported
Role of Lysosomes
Membrane sacs that contain digestive enzymes - hydrolytic enzymes
Role of Vacuoles
Found in plants and animal cells. Used for storage of fluid nutrients and waste products
What is the route of how proteins are made?
Nuclear Envelope
Endoplasmic reticulum - rough and smooth
Golgi Apparatus
Transport vesicles
Lysosomes
Vacuoles
Role of Peroxisomes
Breakdown amino acids and fatty acids by an oxidation reaction in the liver or kidney
Structure and Role of Mitochondria
Double membrane bound organelle found in most eukaryotic cells.
Site of Respiration, uses ATP to generate chemical energy
Contains its own DNA
Structure and Role of Cell Membrane
Controls and entry and exit of substances
Phospholipid belayer - hydrophilic head (attracts water) and hydrophobic tail (repels water)
Contains protein channels for transport - carrier proteins, aquaporins
Name 5 functions of membranes
Compartmentalise Cell
Protect Cells
Control Movement of Molecules
Communication to surrounding cells
Transmit signals
Function of Ribosomes
They read mRNA and bind to tRNA to synthesize polypeptides and proteins
How do proteins move between compartments?
Nuclear pores
Across membranes via protein translocators
Within vesicles (e.g. between ER and Golgi)
Sorting Proteins Co-translational Import Route
Nucleus, RER, Golgi (vesicles), exported outside of the cell or goes to the lysosome
Sorting Proteins Post-translational Import
Nucleus, Ribosome
Nucleus, Ribosome, Mitochondria, Peroxisome
Role of Chaperones in protein folding
Help proteins to fold properly during protein synthesis and stop them from unwinding during translocation
Explain how single recognition particle works
Synthesis begins on a free ribosome
When the polypeptide chain contians about 20 amino acids the ER signal sequence is recognised by the sinal recognition particle
Partical binds to sinal seqeunce and protein synthesis stops
The complex of the ribosome and signal recognition particle encounter a specific signal recognition particle receptor (docking protein) on the ER
This caused the polypeptide chain to be directed to the protein translocator. The signal recognition particle and is receptor are released
Protein synthesis can continue and polypeptides can then go through the membrane via a channel protein
The single sequence maybe cleaved off by an enzyme called signal peptidase, Some proteins do not undergo this step but instead retain their sig\nl sequence.
