Flashcards in Lecture 9 Deck (45)
What are proteins?
Proteins – the most abundant of all biomolecules
Other biomolecules – nucleic acid, carbohydrates, lipids–
Proteins are required for building and repair of body tissues
Involved in structural support & bodily movement
Can also be a source of energy
Antibodies that defend the body against infectious agents
Transport proteins – hemoglobin and myoglobin
The structure of a protein determines its function
What are proteins made of?
Proteins (polypeptides) are organic compounds made of amino acids
Amino acids – basic building blocks of all proteins
The end products of protein digestion are amino acids
Amino acids are joined together by peptide bonds between the carboxyl and amino groups (amine)
Growth, repair and maintenance of all cells depends on amino acids
How many amino acids?
There are 20 different natural amino acids
Each with a different R group (side chain structure determines the identity)
10 of the 20 amino acids cannot be produced in the body
Must be supplied through the diet in the form of protein – known as essential amino acids
Primary purpose of amino acids:
The synthesis of body proteins, including plasma, intracellular and structural protein
What elements are in proteins?
Proteins contain the same elements as carbohydrates and fat, with the addition of nitrogen
Carbon, hydrogen, oxygen and nitrogen
what are primary protein structures?
The sequence (linear) in which amino acids are lined up and connected by peptide bonds
Dipeptide – Two amino acids combine
Polypeptide – Many (> 3) amino acids combine
The long repetitive sequence of amino acids that make a continuous chain is called the protein’s backbone
what are secondary protein structures?
Twisting or folding of the protein chain (primary) into a spiral or coil
Called α helix; or parallel strands – called β pleated sheet
Held by hydrogen bonds between the H of the NH of one amino acid and the O of the C=O of another amino acid
what are tertiary protein structures?
Protein chains folded into specific three-dimensional shape held by:
Disulfide bonds (-S-S- bonds)
This shape is vital for the function of enzymes and the biological activity of other proteins
interplay of sidechains
what are 4arny protein structures?
Combination of several protein units (subunits) with its own complete structure
Example – Hemoglobin
How are chemical structures catalyzed?
All biochemical reactions are catalyzed by enzymes which are proteins
What are cell structure and extracellular matrices composed of?
Structure of cells and extracellular matrix are made from collagen…most abundant protein in the body
What are nucleotides?
The building blocks of DNA and RNA
Determine the genetic structure of life
Units that make up nucleic acids like RNA and DNA
Function to transport and transform cellular energy and regulate enzymes
Most nucleotides are adenine (A), guanine (G) - purine, thymine (T), cytosine (C), pyrimidine and urasil (U) They are joined by hydrogen bonds
What is a gene?
A segment of DNA that contains the information required for the synthesis of a functional biological product is referred to as a GENE
Describe DNA/RNA structure
Structure consist of – A pentose sugar like ribose or deoxyribose, a phosphate or polyphosphate group and a nitrogen containing base
Represented by: N – S – P
Example – Adenosine monophosphate (AMP)
ATP – High energy usable by all body cells
2 phosphoric acid groups added to AMP
What is DNA?
DNA - Deoxyribonucleic acid
Long-term information storage (a chemical information storage medium)
A nucleic acid that contain genetic instructions
Most DNA is located in the cell nucleus (called nuclear DNA)
Nearly every cell in a person’s body has the same DNA
What does the spine of DNA look like?
Has a spine ( backbone) of alternating (repeating) deoxyribose (sugar) and phosphate molecule covalently bonded in a long chain
The 2 chains are held together by hydrogen bonds between the bases
Each sugar group is attached to a nucleotide / nitrogenous base (responsible for genetic coding
Describe the layers of DNA structure
DNA polynucleotide chains pair up with one another (primary structure)
Bond together in twisted double strand (double helix)
Double-helix wraps around some proteins (tertiary structure)
Describe DNA replication
DNA replication or DNA synthesis, is the process of copying a double-stranded DNA strand
The strands separate at the nucleotide base
Each chain becomes a template for the new chain (double helix)
Each chain attract additional nucleotide
A chain of nucleotides produced by transcription of DNA
Single chain or strand
The sugar is ribose and the base thymine is replaced by uracil
RNA is made up of – nucleotides (with a nitrogenous base), a ribose sugar, and a phosphate group
RNA – transfer information from DNA to the ribosome
How does transcription work?
When a particular protein is needed by a cell –
DNA chain separates
One chain act as a template for RNA
DNA sequence is enzymatically copied by an RNA polymerase to produce a complementary RNA (mRNA)
In other words, the transfer of genetic information from DNA into RNA
What is a codon?
Codon – Grouping of three nucleotides on a mRNA molecule
Codes for one of the 20 natural amino acids
What is mRNA?
mRNA / messenger RNA
Contain/carry the information on the primary sequence of amino acids in a protein to be synthesized (in the cytoplasm)
What is tRNA
tRNA / Transfer RNA
"reads" the mRNA codon by using its own anticodon
carries the amino acid to be incorporated into the developing protein
each tRNA is specific for a certain amino acid
What is rRNA
rRNA / Ribosomal RNA
rRNA and protein combine to form a nucleoprotein called a ribosome
Ribosome serves as the site and carries the enzyme necessary for protein synthesis
What is a mutation?
A change in copying DNA
Changes in a genomic sequence
Could be inherited or acquired
Changes could be harmful or have no effect
The bases of Sickle Cell Disease – Change of one amino acid in the hemoglobin structure
What is Fragile X?
Fragile X – DNA test (genetic material)
Fragile X is the most common inherited cause of mental impairment and the most common known cause of autism
What is Downs Syndrome
Downs Syndrome – Chromosome 21 abnormality
What is cystic fibrosis
Affects the entire body, causing progressive disability and often early death (lungs, muscle)
What is a solution
A solution is a homogeneous and transparent mixture involving – solute(s) and solvent
Solute – the dissolved substance
Present in lesser amount
Solvent – the substance in which the solute is dissolved
A solution can pass through a filter
What is an ionic solute?
An ionic solute dissolves in water (polar solvent) because the polar water molecules attract and pulls the ions into solution where they become hydrated
Example NaCl crystals undergo
hydration as water molecules surround each ion and pulls it into solution