Lecture 2 - final review.docx

6 Pages
111 Views
Unlock Document

Department
Biochem & Molecular Biology
Course
BIOC 2300
Professor
Dr.Carmichael Wallace
Semester
Winter

Description
Lecture 2 Water - Has a unique polar structure - An important property involves its interaction with a wide range of substances Biological Membranes - Thin, flexible, stable sheet-like structures that enclose all living cells and organelles - Noncovalent two-dimensional supramolecular complexes - Selective physical barriers - Phospholipid bilayer has integral and peripheral membrane proteins - Hydrophilic head facing out, hydrophobic tail facing in Self-assembly - Many biomolecules spontaneously undergo self-assembly into supermolecular structures. Ex: ribosomes, large protein complexes like sarcomeres and proteasomes. - They do this because they already have the steric information required - In some cases the assembly process requires assistance. Ex. The folding of some proteins require the help of molecular chaperones Molecular Machines - Many multisubunit complexes involved in cellular processes function as molecular machines - Molecular machines = physical entities with moving parts that perform work, the product of force and distance Molecular Crowding - The interior space within cells is dense and crowded - The excluded volume (volume occupied by macromolecules) may be between 20-40% o Non-specific steric repulsion prevents the introduction of additional macromolecules o Remaining space is available for small molecules - Crowded, not dense, because macromolecules of each type are only present in low numbers - Crowding is an important factor in biochemical reaction rates, protein folding, protein-protein binding, chromosome structure, gene expression, and signal transduction Signal transduction= the process that organisms use to receive and interpret information - Reception, transduction, response o Reception = a signal molecules (ligand) binds to and activates a receptor o Transduction = this binding triggers a change in the three dimensional structure of the receptor which results in the conversion of a primary message or signal to a secondary message, often across a membrane barrier o Response = once initiated, the internal signal causes a cascade of events that involve covalent modification (ex. Phosphorylation) or intracellular proteins. Results of this process include changes in enzyme activities and/or gene expression, cytoskeletal rearrangements, cell movement, or cell cycle progression Prokaryotes - Include bacteria and archaea - Common features: cell wall, plasma membranes, circular DNA, and no membrane-bound organelles - Often have flagellum to allow cell movements o Cell Wall  Complex semi-rigid structure used primarily for support and protection  Primarily composed of peptidoglycan  Cells that retain crystal violet stain are gram-positive (wall is a single thick layer of peptidoglycans), those that do not are gram- negative (more complex) o Plasma Membrane  Directly inside the cell wall  Phospholipid bilayer  Selectively permeable membrane that may be involved in photosynthesis or respiration o Cytoplasm  Prokaryotic cells DO have functional compartments, despite lack of internal membranes • Nucleoid – centrally located, contains the circular chromosome • Also contains small DNA plamids • Inclusion bodies are large granules that contain organic or inorganic compounds o Pili and Flagella – external appendages  Pili (pilus) are for attachement and sex  Flagella (flagellum) used for locomotion Structure of Eukaryotic Cells  structurally complex - Membrane-bound organelles and the endomembrane system increase surface area for chemical reactions o Endomembrane system = extensive set of interconnecting internal membranes that divide the cell into functional c
More Less

Related notes for BIOC 2300

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit