Energy and Protein Synthesis

Energy and protein synthesis

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Cellular metabolism

cells carry out a large number of chemical reactions to maintain Homeostasis

Need energy = AEROBIC respiration ATP

ATP = ADENOSINE TRIPHOSPHATE

ADENINE AND 3 PHOPHATES AND RIBOSE 

GLYCOLYSIS, KREBS CYCLE, ELECTRON TRANSPORT

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Glycolysis

occurs in the Cytoplasm

6 Carbon Glucose breakdown to 2 3C pyrine acid units

NET GAIN OF 2 ATP

AEROBIC RESPIRATION

oxygen present

krebs cycle

cytochrome system

Mitochondria net harvest = 36 ATP

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Cytochrome System

Produces most of the ATP

Oxygen occupies the final position in the electron transport

Sometimes oxygen incorrectly bonds without electrons 

Free radical - o2, OH, h2, O2

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Antioxidents

Free radicals are cleared from the cell

Ageing reduces this antioxident

GSH - plasma reduced Gluthamine

GSSG -  Oxidised gluthathione

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Proteins Synthesis

Some provide structural support for cells, whilst others act as enzymes

DNA TRANSCRIBED into MRNA

mRNA TRANSLATED into amino acids

Amino acid folds into specific proteins

DNA transcription transfer DNA into RNA

Many copies of RNA are made

They act as the template for Protein synthesis

RNA copy of gene is mRNA

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DNA and RNA

DNA - constructed by nucleotides

polymers of nucleotides

Base, sugar and phosphates

Five bases and two sugars found in nature

Purines - ADENINE AND GUANINE,

two nitrogenous rings = differ in the position of the amino group

Pyrimidines = Cytosine, Thymine, Uracil

one nitrogenous rings

differ in nature and position

of side group and methyle group

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RNA

Consist of polynucleotide chain

its consists of only one strand

Pentose sugar is ribose

uracil replaces thymine

Only one strand of mRNA is needed to synthesize proteins.

mRNA exists in single strands

mRNA - messenger RNA

tRNA - transfer RNA

rRNA - ribosomal RNA

snRNA - small nuclear RNA

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Functions of RNA

mRNA is a copy of DNA 

mRNA is read by ribosome

Amino acid brought to ribosome by tRNA

smRNA forms complexes with proteins

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Protein degradation, Proteasome, Ubiquitin

Destruction of proteins is as important for the maintanace of protein homeotstasis in cells - Protein Degradation.

Proteasome - Deals primarily with endogeneous proteins

transcription factors, cyclins, protein encoded by viruses

Proteins that are unfolded incorrectly of translation.

Ubiquitin - a small protein made of 76 amino acids

Core proteins - 2 copies of 14 different proteins assembled in groups of 7

4 rings stacked on each other

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Important

Regulatory practice - made of 19 different proteins

6 of these are ATPases

Some of the subunit have sites that recognise ubiquitin.

Process - proteins to be destructed are conjunctionto a molecule of ubiquitin which binds to lysine.

Complex binds to ubiquitin recognising site on regulatroy particle.

Protein is unfolded by ATPases

The unfolded protein is moved into the central cavity

Active sites on the inner surfaces of the middle break various specific peptide bonds

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