Summer Bio Week 3

What elements are proteins made up of?

Carbon, Hydrogen, Oxygen, Nitrogen, Sulfur (sometimes)

Enzymes

organic catalysts that start and speed up chem rxn’s

*Every rxn requires it’s own enzyme

What is the reactant in a enzyme reaction called?

A substrate

Contractile proteins

For movement

Antibodies

Proteins made by white blood cells that inactivate and destroy viruses and bacteria

*They are specific for specific antigens

Transport proteins

proteins that carry molecules in and out of cells

Structural proteins

contain amino acids with sulfur (helps to stabilize protein)

Storage proteins

Becomes incorporated into growth tissue

*not used for energy to burn

Hormones

Allows regulation of an organism’s activity

R-group

Variable side chain gives an amino acid its chemical properties (poplar, nonpolar, acidic, basic)

If an R group contains these chemicals it is polar…

Sulfur, Oxygen, Nitrogen

How does polarity affect amino acids?

It affects how they fold into the proper shape

Where are polar amino acids located?

OUTSIDE (so they can interact with water)

Where are nonpolar amino acids located?

INSIDE (bc they do not interact with water)

Peptide bond

A covalent bond between the carboxyl group of one amino acid and the amino group of the next amino acid

*Look for the C that is double-bonded to O

How does a Polypeptide become a Functional Protein?

1. Needs a min of 50 amino acids

2. A specific 3D shape formed through several levels of structure

Primary structure

precise order of amino acids in a polypeptide chain

Secondary Structure

The polypeptide folds into small repeated patterns

*R group is NOT involved

ex- cobwebs

In secondary structure, what are the structures stabilized by?

Hydrogen bonds between the amino group of 1 amino acid and the carboxyl group of another

Tertiary structure

Created the final 3D shape of a single polypeptide formed by interactions b/t R groups

ex- insulin

What is a disulfide bridge?

S-S in structural proteins

Quaternary structure

2 or more chains fit together to make 1 functional protein

ex- hemoglobin

deNATURED

A protein changes shape and can’t function

Temperature affects protein function

Too hot: can permanently denature

Too cold: can slow down protein function (usually reversible)

What temperature is homeostasis for humans?

37 °C

Changes in pH affect protein function

most cells - pH 7

digestive(stomach) proteins- pH 2

Intestine- pH 8 or 9

Salts affect protein function

Ions/charges attract parts of the protein, pulling it out of shape

ex- chemically straightening hair

Is the primary structure of a protein affected by denaturing?

NOPE because the pep bonds don’t break

*NUMBER and SEQUENCE of amino acids don’t change

What elements are in Nucleic Acids?

Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus

Monomer of a nucleic acid

Nucleotide

What is DNA?

The genetic code for ALL living things

What does DNA code for?

sequences of proteins (that make up a structure and allow all metabolic rxn’s)

Gene

a small portion of DNA

Genome

ALL the genes in an organism

Chromosomes

DNA is wrapped around protein structures to make a chromosomes

*we have 46

Transcription

the process that copies the DNA→RNA

Translation

the process that reads the RNA and translates the message into amino acids

Where is DNA found in a Eukaryote?

Nucleus

Where is DNA found in a Prokaryote?

floating in cytoplasm

What shape is DNA

double helix

Who discovered the shape of DNA?

James Watson, Francis Crick, Roslyn Franklin

What does Adenine bond with?

Thymine (DNA)

Uracil (RNA)

ANTIparallel

the 2 strands of DNA run side by side in opposite directions

What bonds together the base pairs?

HYDROGEN BONDS

What does RNA do?

Copies the DNA and brings it to the ribosomes so the proteins can be synthesized

Messenger RNA (mRNA)

a copy of DNA

Transfer RNA (tRNA)

helps in the process of translation

Ribosomal RNA (rRNA)

found in all ribosomes and helps in translation

What are the groups in brackets called?

Codons- code for a single amino acid

Purine

Guanine and Adenine (2 rings)

Pyrimidine

Thymine and Cytosine (1 ring)

How many strands is DNA?

2

How many strands is RNA?

1

What is the sugar in DNA?

deoxyribose

What is the sugar in RNA?

ribose

DNA helicase (enzyme)

unzips the DNA molecule by breaking hydrogen bonds

RNA polymerase (enzyme)

binds to a region of the DNA called the promoter

What happens when the it reaches the termination signal?

RNA polymerase will break loose from DNA and the newly made mRNA will be released

Where does transcription occur?

Nucleus

What is the direction of transcription?

5¹ → 3¹

Introns

uncoded regions of mRNA that are cut out

Why are the introns cut out?

It reduces chance of mutation

Exons

coded regions of mRNA that are spliced making the final mRNA transcript

How many codons combos are there?

64

Where does translation occur?

Cytoplasm

What is needed for translation to occur?

1. edited mRNA

2. Ribosome

3. tRNA

What is this?

tRNA

Anticodons

have the corresponding nitrogen bases to the mRNA

What happens to the amino acids during TRANSLATION?

they form peptide bonds with adjacent amino acids and form a polypeptide

Stop codons

UAA, UAG, UGA