BIO 311C Concept Map

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"Photo"

Retrieve energy including Light Reactions

Ribosomal subunits and other parts dissociate

Release factor promotes hydrolysis of the bond between tRNA in P site and the last amino acid.

A ribosome reaches the stop codon and the A site accepts a release factor

Cellular Respiration

Photosynthesis

"Synthesis"

Lysosome

Breaks down molecules and recycles them

Endocytosis, three types

Pinocytosis

Phagocytosis

Receptor mediated

Gene Expression

RNA Modifications

RNA splicing

Introns are cut out and exons are spliced together

5' Cap and Poly A Tail

5' cap and Poly A tail are added to the two ends of pre-mRNA molecule in otder to facilitate the export of mature RNA from the nucleus, protect the mRNA from degrading, and help ribosomes attach to the 5' end of the mRNA when it is in the cytoplasm

Transcription

RNA transcript is realsed and polymerase detaches from the DNA

Polymerase moves downstream, unwinding the DNA and elongating the RNA transcription in 5' to 3' direction

RNA Pol binds to promoter, DNA strands unwind, Pol initiates RNA synthesis at start point

Transcription in Eukaryotes

Other transcription factors bind the DNA along with RNA Pol II, forming transcription initiation complex

Transcription factors bind to DNA before RNA Pol II binds to it

TATA box nucleotide sequence (promoter)

Translation

Three Steps

Elongation Cycle

Translocation

Ribosome transolcates tRNA from A site to P site. Empty tRNA in P site moved to E site to get released.

Peptide bond formation

Codon Recognition

Anticodon of aminoacyl tRNA base pairs with complementary mRNA codon in A site. Binds and proceeds

Large ribosomal unit completes initiation complex. Initiation factors in charge of connection of all translation components.

Small ribosomal unit binds to mRNA. Initiator tRNA binds with start codon

Process in which protein is synthesized

Cell Signaling

Membrane Receptors

Ion Channel receptor

Membrane bound receptor undergoes conformational change, allows for passage of ions

Tyrosine kinase receptor

Allows transfer of phosphate from ATP to tyrosine kinase regions of dimer

G-protein coupled receptor

Cell surgace transmembrane receptor that works with help of G protein

Signal Molecules

Hydrophilic

Receptor on/in plasma membrane

Hydrophobic

Receptor in cell nucleus

Receptor in cell cytoplasm

Types of cell signaling

Local

Synaptic

Neurotransmitters released and diffuses across synapse, stimulating target cell

Paracrine

Direct signaling

Stages of cell signaling

Cellular response: Transduced signal triggers response

Transduction: Receptor protein changes when signal molecule binds to it. Signal conveyed to form that can bring cellular response. Signal transduction pathway

Reception: Signal molecule binds to receptor protein located at cell's surface

Gene Regulation

Transcription factors

Specific transcription lead to increased expression

Distal control elements are enhancers that are located upstream/downstream of a gene

Activators bind to enhancer and bends sequence

General factors leads to basal level transcription

Proximal control elements are close to promoter

Transcription factors bind to proximal elements and transcription is low

Allows RNA Pol II to bind

Repressor binds to enhancer and prevents RNA Pol II to bind

Tryptophan

Tryptophan present, repressor active, operon off

Tryptophan absent, repressor inactivated, operon on

Negative regulator because binds to repressor

Amino acid

cAMP levels

Lactose and glucose present means low cAMP levels and CAP is inactivated

Lactose present, glucose absent means high cAMP levels and activated CAP

Operon on

Lactose present, repressor inactive, operon on

Operon off

Lactose absent, repressor on, operon off

Lac Operon

Required for transport and metabolism of lactose

Lac I is lac repressor

Lac A adds acidicyl group to lactoes

Lac Y takes in lactose

Lac Z forms mRNA

Prokaryotes

Operator is not in Eukaryotes

Multiple genes controlled by same promoter

Operons are present

DNA Packaging

DNA packaged with proteins into chromatin

Histone core is a protein that binds the DNA

Nucleosomes formed when DNA wraps around histone twice

Interactions between nucleosomes cause thin fiber to coil or fold into thicker fiber

Tight helical fiber needs help of H1

Nucleosomes strung together

H1 is not a part of the core

H1, H2A, H2B, H3, H4

DNA Replication

Steps of Replication

Termination

Elongation

Primer starts making leading strand and uses the existing strand as a template strand. DNA Pol III puts on new bases and lagging strand is synthesized in okazaki fragments. DNA ligase attaches these fragments together

Initiation

Begins at ORI, helicase unwinds DNA. Topoisomerase releases tension. RNA primers are created

DNA structure

Bases

Cytosine

Guanine

Thymine

Adenine

Semi-conservative

Messeleson and Stahl

Strands separated and template synthesizes new complementary strand

Cell Division

Cell communication

Cells signals one another to tell other cells to begin replication, starting at the phospholipid bilayer

Signal molecules are attached to the phospholipid bilayer and cellular processes begin with the attachment to a receptor molecule

DNA Synthesis

Origin of Replication

Point in DNA where replication begins

Replication fork

Where the DNA begins to separate

Lagging strand

Synthesizes in direction away from fork

Leading Strand

Synthesizes in direction towards replication fork

Enzymes involved with DNA

Topoisomerase

Relieves strain on DNA strands

Ligase

Connects DNA

DNA Polymerase I

Removes RNA primers and replaces with DNA

DNA Polymerase III

Synthesizes new DNA strands

Primase

Creates RNA primer and attaches on at 5' end of leading strand and multiple on lagging strand