Midterm 1 Flashcards
What are cells?
Small membrane enclosed units filled with concentrated aqueous solution of chemicals and capable of creating copies of themselves by growing and dividing into two.
What are the 4 properties of all cells?
Vary enormous in appearence an function
They posses the same molecular machinery
All cells evolved from the same ancestrall cell
Genes provide instructions for cell function, form and behavior.
Describe cell theory:
- Everything that id alive is made at least of one cell.
- All living organisms owe their structure and function to the fact that they are made of cells.
- All cell arise from pre-existing cells.
What are the two domains of prokaryotes?
Archea and bacteria.
What is the main characteristic of prokaryotes?
They don’t have a nucleus nor membrane-enclosed organelles.
How is the genome of prokaryotes?
It carries very little superfluous genetic package and it is relatively small.
What are the three different forms that prokaryotes can adopt?
- Spherical
- Rod like
- Corkshrew
What is the main characteristic of eukaryotes?
They are bigger and more elaborated, they have a nucleus and membrane enclosed organelles.
Describe nucleus:
Has a double membrane called nuclear envelope that contains nuclear pores.
Contains DNA molecules that become visible as chromosome in M-phase.
Describe mitochondria:
Have two separate membranes the internal is enfolded forming cristae.
Perform cellular respiration
Contain their own DNA and reproduce by dividing in two.
Describe chloroplasts:
They are present only in plants
They have two membranes plus internal stacks of membranes that contain chlorophyll.
Describe the Endoplasmic reticulum:
Irregular maze of interconnected space enclosed by a membrane. It creates cell membrane components and material destined for export.
Describe Golgi apparatus:
Stacks of flattened membrane enclosed sacs that modifies and package molecules coming from the ER.
How is the inside of the Golgi apparatus and of vesicles?
Is similar to the extracellular environment.
Describe lysosomes:
Small regularly shaped vesicles that make intracellular digestion and release nutrients.
Describe peroxisomes:
They provide a safe environment for reaction involving hydrogen peroxide.
Describe cytosol:
The largest cell component not contained within intracellular membranes and is the site of many chemical reactions.
What are the three components of the cytoskeleton?
- Actin filaments
- Intermediate filaments
- Microtubules
What are motor proteins:
They use energy stored in ATP to trundle along the cytoskeleton.
What are the 4 factors that make think that the eukaryotic cell originated as a predator?
1) Flexible cell membrane
2) Large size
3) Cytoskeleton to move and eat
4) Nuclear envelop to protect DNA
What is the function of enzyme?
Catalyze covalent bond formation and breakage.
What is the function of structural proteins?
Provide mechanical support to cells and tissues.
What is the function of storage protein?
Store amino acids and ions.
What is the function of receptor proteins?
Carry extracellular signals from cell to cell
What is the function of gene regulatory proteins?
To bind to DNA to switch gene expression on or off.
What is the side chain of a molecule?
The part of amino acid that is not involved in the formation of peptide bonds.
What are the four forces that constrain the free rotation of polypeptides?
1) Hydrogen bonds
2) Van der Waals forces
3) Electrostatic attraction
4) Hydrophobic interaction
What are the three types of interaction within a protein?
1) Backbone-backbone interaction
2) Backbone- side chain
3) Side chain- Side chain
What is conformation?
Final folded structure of a protein.
What is denaturation?
Nonfunctional configuration of a protein.
In which 2 ways do chaperone proteins assist protein folding?
1) Some of them binds to the folding proteins and help them folding to the most energetically favorable pathway
2) they forms isolation chambers in which each polypeptide can fold without the risk of forming aggregates.
Describe backbone model:
Show the overall organization of the polypeptide chain and provide a straightforward way of comparing the structure of related proteins.
Describe ribbon model:
show the polypeptide backbone in a way that emphasizes its various folds.