Podcast
Questions and Answers
During periods of fasting, which process is most directly responsible for maintaining blood lipid concentrations?
During periods of fasting, which process is most directly responsible for maintaining blood lipid concentrations?
- Increased cholesterol synthesis by the liver for cell membrane repair.
- Direct absorption of triglycerides from the small intestine.
- Increased synthesis of essential fatty acids by the liver.
- Hydrolysis of triglycerides stored in adipose tissue. (correct)
How do enzymes facilitate biochemical reactions within the human body?
How do enzymes facilitate biochemical reactions within the human body?
- By increasing the amount of energy required for reactions to occur.
- By reducing the energy needed for reactions and acting on a specific substrate. (correct)
- By being consumed during the reaction process, thus providing energy.
- By permanently altering the structure of the substrate.
In what way does the liver contribute to both lipid metabolism and overall cholesterol balance in the body?
In what way does the liver contribute to both lipid metabolism and overall cholesterol balance in the body?
- By exclusively synthesizing cholesterol and preventing its removal from the body.
- By breaking down saturated fats into essential fatty acids.
- By directly storing excess cholesterol in adipose tissue.
- By synthesizing triglycerides, phospholipids, and lipoproteins and by synthesizing/releasing cholesterol for bile salt production and cell membrane structure. (correct)
Which type of chemical reaction is most directly involved in the growth and repair of tissues?
Which type of chemical reaction is most directly involved in the growth and repair of tissues?
If a patient is diagnosed with a deficiency in the digestion and absorption of fats, a deficiency in which vitamins is most likely to occur?
If a patient is diagnosed with a deficiency in the digestion and absorption of fats, a deficiency in which vitamins is most likely to occur?
How do the roles of DNA and RNA differ concerning protein synthesis and genetic information?
How do the roles of DNA and RNA differ concerning protein synthesis and genetic information?
What is the primary distinction between essential and non-essential amino acids, considering their source and role in the human body?
What is the primary distinction between essential and non-essential amino acids, considering their source and role in the human body?
What critical role is played by water and salts, as inorganic compounds, in facilitating metabolic processes and maintaining cellular function?
What critical role is played by water and salts, as inorganic compounds, in facilitating metabolic processes and maintaining cellular function?
Which statement accurately contrasts catabolism and anabolism in terms of their processes and roles in the body?
Which statement accurately contrasts catabolism and anabolism in terms of their processes and roles in the body?
When an enzyme is exposed to extreme heat, and its function is impaired, what is the most likely reason for this loss of function?
When an enzyme is exposed to extreme heat, and its function is impaired, what is the most likely reason for this loss of function?
Flashcards
Carbohydrates
Carbohydrates
Compounds of carbon, hydrogen, and oxygen, powering cells.
Monosaccharides
Monosaccharides
Simple sugars like glucose, fructose, and galactose.
Oligosaccharides
Oligosaccharides
Chains of two to ten monosaccharides.
Disaccharides
Disaccharides
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Polysaccharides
Polysaccharides
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Proteins
Proteins
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Peptide Bonds
Peptide Bonds
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Lipids
Lipids
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Saturated Fats
Saturated Fats
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Vitamins
Vitamins
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Study Notes
Carbohydrates (Saccharides)
- Compounds composed of carbon, hydrogen, and oxygen atoms
- Act as primary fuel source for powering cellular processes
- Four main categories:
- Monosaccharides (simple sugars)
- Oligosaccharides (2-10 monosaccharides)
- Disaccharides (double sugars)
- Polysaccharides (complex sugars)
Simple Sugars (Monosaccharides)
- Glucose (dextrose) prevalent in blood
- Fructose found in fruit juices and honey
- Galactose exists in milk and dairy products
- The liver converts both fructose and galactose into glucose
- Ribose and deoxyribose are used in manufacturing RNA and DNA
Disaccharides
- Require breakdown into monosaccharides for cellular utilization
- Sucrose known as table sugar
- Maltose referred to as malt sugar
- Lactose present in milk sugar
Polysaccharides
- Consist of long chains of linked monosaccharides
- Plant starch sourced from potatoes, rice, and peas
- Animal starch referred to as glycogen
- Cellulose functions as indigestible fiber
Proteins
- Abundant organic compounds composed of carbon, oxygen, hydrogen, and nitrogen
- Include enzymes, plasma proteins, muscle components (actin, myosin), hormones, and antibodies
- Supply energy when digested into amino acids
- Structural proteins:
- Collagen provides strength to ligaments and connective tissues
- Keratin prevents water loss
- Cell membrane proteins function as receptors and carriers for specific molecules
- Twenty-one different amino acids constitute proteins
Peptides, Polypeptides & Amino Acids
- Peptide bonds link amino acids in protein molecules
- Polypeptide consists of a chain of many amino acids with specialized functions; considered a protein when exceeding 100 molecules
- Most amino acids are synthesized by the adult body
- Essential amino acids, needed for growth and repair, must be obtained from diet
- Non-essential amino acids are produced by the liver and do not require dietary intake
Lipids
- Contain carbon, hydrogen, and oxygen; they are not water-soluble
- Dissolve in other lipids, oils, ether, chloroform, or alcohol
- Common types include triglycerides, phospholipids, and steroids (including cholesterol)
- Triglycerides (fats) are the most common and are made of glycerol and fatty acids
- Prostaglandins are derivatives of essential fatty acids
Saturated, Unsaturated, and Monounsaturated Fats
- Saturated fats are present in meats, eggs, milk, animal fat, palm oil, and coconut oil and pose a cardiovascular risk if excessively consumed
- Unsaturated fats exist in nuts, seeds, and plant oils
- Monounsaturated fats, the healthiest type, can be found in olive, peanut, and canola oils
Lipid Functions
- Supply energy via triglyceride hydrolysis in the presence of water
- Fatty acids and glycerol are released, absorbed, and transported in lymph and blood
- Fatty acid portions react to form acetyl coenzyme A (acetyl CoA) through beta oxidation
- Excess acetyl CoA converts into ketone bodies like acetone
- The liver does not synthesize essential fatty acids
- The liver synthesizes triglycerides, phospholipids, and lipoproteins from free fatty acids in blood
- Cholesterol is synthesized and released by the liver, removed from blood for bile excretion and bile salt production, and provides structural material for cell membranes
- Triglycerides are stored in adipose tissue
- Triglycerides can be hydrolyzed to free fatty acids and glycerol when blood lipid concentrations decrease, such as during fasting
Vitamins
- Organic compounds required for normal metabolism
- Classified by solubility:
- Fat-soluble (A, D, E, K) vitamins are absorbed with bile salts in the small intestine and can accumulate in tissues, requiring controlled intake
- Water-soluble (B vitamins, C)
Nucleic Acids
- Large organic molecules carrying genetic information or forming structures within cells
- Two classes: DNA and RNA
- DNA: genetic material arranged in genes, encoding protein-building information and directing structural protein synthesis for inherited characteristics
- RNA: crucial for protein manufacturing using DNA information (mRNA, tRNA, rRNA)
Inorganic Compounds
- Essential for fluid balance and material transport through cell membranes
- Includes oxygen, carbon dioxide, salts, and water
- Solutes dissolve in water, increasing likelihood of metabolic reactions
- Watery (aqueous) blood portion carries oxygen, salts, sugars, and vitamins
- Oxygen enters through respiratory organs and is transported by red blood cells (erythrocytes)
- Organelles use oxygen to release energy from nutrients for cellular metabolism
- Salts comprise oppositely charged ions in tissues and fluids
- Salt ions are important for transporting substances, muscle contractions, and nerve impulses
Chemical Reactions and Enzymes
- Form or break chemical bonds, altering chemical substances; enzymes catalyze reactions to sustain life
- Catalysts speed up reactions without being consumed
- Enzymes assist in digestion, drug metabolism, and protein formation
- Enzymes reduce energy needed for metabolic reactions by acting on a substrate
- Three-dimensional shapes enable substrate identification, forming an enzyme-substrate complex
- The active site temporarily combines with substrate molecules
- Enzymes are reversible and can be altered by heat, electricity, chemical radiation, or extreme pH levels
- Denaturing changes enzyme structure
- Some enzymes require a non-protein component (co-factor) such as elements, ions, or non-protein organic coenzymes for activation
Types of Chemical Reactions
- Synthesis reactions occur when reactants bond to form complex products and require energy (A + B → AB), important for growth and repair
- Decomposition reactions: bonds break down complex molecules into simpler ones (AB → A + B), essential during digestion
- Exchange reactions: decomposition and synthesis occur to produce new compounds (AB + CD → AD + CB)
- Reversible reactions products can revert to reactants within cellular metabolism, maintaining homeostasis
Catabolism and Anabolism
- Catabolism: breaks down larger molecules into smaller ones, converting energy into ATP; excessive catabolism leads to tissue wasting
- Anabolism: builds larger substances from smaller ones using ATP; simple nutrients build cellular chemicals to sustain life
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