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Anatomy and Physiology Chapter 4
Anatomy and Physiology (BI2024)
Pittsburg State University
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chapter 4
Cellular Metabolism
In Class Notes a. Metabolism i. Anabolism 1. building - taking (subunits to build new protein) ii. Catabolism
Breakdown - Digestive (subunits of amino acid) b. Anabolism i. Dehydration synthesis 1. Monosaccharide to polysaccharide 2. Amino acids and protein. c. Enzymes - catalyze reactions i. Allows reactions to speed d. Cellular Energy i. Cellular respiration - occurs in mitochondria 1. Glycolysis - breakdown of glucose 2. Citric acid (knees) cycle 3. Electron transport chain e. Genetic information i. DNA (Deoxyribonucleic acid) ii. Gene
“Unit of heredity” iii. Genome
2% codes of proteins
Most genomes is for regulation f. Protein synthesis i. Transcription - in nucleus 1. Copies DNA Template into RNA message ii. Translation - in cytoplasm
Converts RNA Message into protein
Book Summary a. Introduction A cell continuously carries on thousands of metabolic reactions that maintain life and enable cell specialization. Cellular metabolism acquires, stores, and releases energy. b. Metabolic Reactions i. Anabolism
Anabolism builds large molecules from smaller molecules.
In dehydration synthesis, water forms as smaller join by sharing atoms.
Carbohydrates are synthesized from monosaccharides, triglycerides from glycerol and fatty acids, proteins from amino acids, and nucleic acids from nucleotides ii. Catabolism
Catabolism breaks down large molecules into smaller ones.
In hydrolysis, a water molecules is split as an enzyme breaks the bond between two parts of a molecule.
Hydrolysis breaks down carbohydrates into monosaccharides, triglycerides into glycerol and fatty acids, proteins into amino acids, and nucleic acids into nucleotides. c. Control of Metabolic Reactions Enzymes control metabolic reactions, which include many specific chemical changes. i. Enzyme action
Enzymes lower the amount of energy required to start chemical reactions.
Enzymes are molecules that promote metabolic reaction without being consumed (catalysis).
An enzyme acts upon a specific substrate molecule.
The shape of an enzyme molecule fits the shape of its substrate at the active site.
When an enzyme combines with its substrate, the substrate changes, a product forms, and the enzyme is released in its original form.
The rate of an enzyme-controlled reaction depends partly upon the numbers of enzymes and substrate molecules and the enzyme’s eciency. ii. Enzymes and metabolic pathways
A sequence of enzyme-controlled reactions constitutes a metabolic pathway.
Regulatory enzymes in limited numbers set rates of metabolic pathways.
Regulatory enzymes become saturated when substrate concentrations exceed a certain level. iii. Factors that alter enzymes
A cofactor is a non protein necessary for a specific enzyme to function. It may be a coenzyme, which is organic and can be a vitamin.
Most enzymes are proteins. Harsh conditions undo, or denature, their specific shapes.
Heat, radiation, electricity, certain chemicals, and extreme pH values denature enzymes. d. Energy for Metabolic Reactions
A complete set of genetic instructions is a genome. The part that encodes protein is the exome.
A gene is a DNA sequence that contains the information for making a particular protein. ii. DNA molecules
A DNA molecule consists of two strands of nucleotides wound into a double helix.
The nucleus of a DNA strand are linked in a specific sequence.
The nucleotides of each strand pair with those of the other strand in a complementary fashion (A with T, and G with C). iii. DNA replication
When a cell divides, each new cell requires a copy of the old cell’s genetic information.
DNA molecules replicate during interphase of the cell cycle.
Each new DNA molecule has one old strand and one new strand. f. Protein Synthesis Genes provide instructions for making proteins, which take part in many aspects of cell function. i. The genetic code instructions for making proteins
A sequence of DNA nucleotides encodes a sequence of amino acids.
RNA molecules transfer genetic information from the nucleus to the cytoplasm.
Transcription a. Transcription is the copying of a DNA sequence into an RNA sequence. RNA has ribosomes instead of deoxyribose and uracil instead of thymine. Most RNA molecules are single stranded. b. Messenger RNA (mRNA) molecules consist of nucleotide sequences that are complementary to those of exposed strands of DNA. A codon is an mRNA triplet that specifies a particular amino acid. c. Messenger RNA molecules associate with ribosomes and provide patterns for the synthesis of protein molecules.
Translation a. Translation is protein synthesis. It starts as a ribosome binds to an mRNA molecule. b. Molecules of transfer RNA (tRNA) position amino acids aloon a strand of mRNA. A 3-base sequence
in a tRNA called the anticodon complementary base pairs with the codon in the mRNA. The amino acids that the tRNAs bring to the mRNA form peptide bonds. A polypeptide chain grows and folds into a unique shape.
Anatomy and Physiology Chapter 4
Course: Anatomy and Physiology (BI2024)
University: Pittsburg State University
