ANSC 1111 Test 1

What are the six essential ingested nutrients?

Carbohydrates
Proteins
Fats (lipids)
Vitamins
Minerals
Water

Which nutrients can be used for energy?

Carbohydrates
Proteins
Fats (lipids)

Name three factors that increase water intake.

Physical activity: Exercise and other physical activities increase sweating and water loss through respiration, increasing the body's need for hydration.
Hot or dry environmental conditions: Exposure to hot temperatures or dry climates can lead to increased sweating and evaporation, resulting in greater water loss from the body.
High dietary intake of salt or spicy foods: Consuming salty or spicy foods can increase thirst, prompting individuals to drink more water to maintain fluid balance and proper hydration levels.

Define essential.

Essential refers to something that is necessary, required, or indispensable for proper functioning or health.

Do all animals require the same amount of drinking water? Why or why not?

No, different animals have varying water requirements based on factors like body size, metabolic rate, diet, environmental conditions, and physiological processes like lactation or perspiration.

List the three sources of water within your body.

Ingested liquids, moisture from food, metabolic water produced during cellular respiration

Define osmosis.

Osmosis is the movement of solvent molecules (usually water) across a semipermeable membrane from an area of lower solute concentration to an area of higher solute concentration.

What is the function of mesentery?

Mesentery is a fold of the peritoneum that attaches the intestines to the posterior abdominal wall. Its function includes supporting and supplying blood vessels, nerves, and lymphatics to the intestines.

Define prehension, mastication, deglutition, peristalsis, digestion, fermentation, rumination, absorption and excretion.

Prehension: The process of seizing or grasping food.
Mastication: Chewing of food to break it down into smaller particles.
Deglutition: Swallowing of chewed food.
Peristalsis: Wave-like muscular contractions that propel food along the digestive tract.
Digestion: The breakdown of food into smaller molecules that can be absorbed and used by the body.
Fermentation: Anaerobic breakdown of organic compounds by microorganisms.
Rumination: The process of regurgitating, re-chewing, and re-swallowing food in some animals.
Absorption: The process of taking in substances (nutrients) into cells or tissues.
Excretion: The removal of waste products from the body.

Draw and label the parts of the digestive tract of the groups of animals we have discussed. List the function of each part.

1. Ruminants (e.g., cows, sheep, goats):
a. Mouth: Prehension of food (grazing), initial mechanical breakdown by chewing.
b. Esophagus: Transport of ingested food to the rumen.
c. Rumen: Primary fermentation chamber where microbial digestion of cellulose and other complex carbohydrates occurs.
d. Reticulum: Acts as a staging area for fermentation and regurgitation of cud.
e. Omasum: Absorption of water and nutrients from fermented material.
f. Abomasum: True stomach where gastric juices are secreted for further digestion of protein.
g. Small intestine (duodenum, jejunum, ileum): Digestion and absorption of nutrients such as carbohydrates, proteins, and fats.
h. Large intestine (cecum, colon, rectum): Absorption of water and electrolytes, microbial fermentation of remaining carbohydrates.
2. Monogastric (e.g., humans, pigs, dogs, cats):
a. Mouth: Prehension of food, initial mechanical breakdown by chewing, and secretion of saliva containing enzymes (e.g., amylase).
b. Esophagus: Transport of ingested food to the stomach via peristalsis.
c. Stomach: Mechanical mixing and storage of food, secretion of gastric juices (e.g., hydrochloric acid, pepsin) for chemical digestion of proteins.
d. Small intestine (duodenum, jejunum, ileum): Digestion and absorption of nutrients including carbohydrates, proteins, fats, vitamins, and minerals.
e. Large intestine (cecum, colon, rectum): Absorption of water and electrolytes, formation and storage of feces.

Pt.2

3. Hindgut fermenters (e.g., horses, rabbits):
a. Mouth: Prehension of food, initial mechanical breakdown by chewing.
b. Esophagus: Transport of ingested food to the stomach.
c. Stomach: Limited microbial fermentation due to shorter retention time.
d. Small intestine (duodenum, jejunum, ileum): Digestion and absorption of nutrients similar to monogastric animals.
e. Large intestine (cecum, colon, rectum): Site of extensive microbial fermentation of fibrous plant material, absorption of volatile fatty acids (VFAs) produced by fermentation, and water absorption.

What are the three parts of the Small intestine? Name and list the functions of each.

1. Duodenum:
- Receives partially digested food (chyme) from the stomach.
- Mixes chyme with bile from the liver (via the common bile duct) and digestive enzymes from the pancreas (via the pancreatic duct).
- Neutralizes stomach acid with bicarbonate secreted by the pancreas.
- Continues digestion of carbohydrates, proteins, and fats with the help of pancreatic enzymes and bile.
- Absorbs nutrients such as carbohydrates, proteins, fats, vitamins, and minerals.
2. Jejunum:
- Main site for further digestion of nutrients, particularly carbohydrates, proteins, and fats.
- Absorbs most of the remaining nutrients, including amino acids, fatty acids, glucose, and some vitamins and minerals.
- Contains a rich blood supply and numerous villi and microvilli to maximize absorption surface area.
3. Ileum:
- Completes the digestion and absorption of nutrients that were not absorbed in the duodenum and jejunum.
- Absorbs bile salts and some vitamin B12.
- Plays a role in the immune system, as it contains lymphoid tissue (Peyer's patches) that helps protect against pathogens.

Where does fermentation take place in each of the different types of animals we discussed?

1. Ruminants (e.g., cows, sheep, goats): Fermentation primarily occurs in the rumen, which is the largest compartment of the stomach. The rumen is a specialized fermentation chamber where anaerobic microbes break down fibrous plant material (cellulose, hemicellulose) into volatile fatty acids (VFAs), gases (such as methane), and microbial protein.
2. Monogastric animals (e.g., humans, pigs, dogs, cats): Fermentation in monogastric animals occurs primarily in the large intestine, particularly in the cecum and colon. While fermentation also occurs to a lesser extent in the stomach and small intestine, the majority of microbial fermentation of undigested plant material and fiber occurs in the hindgut. Microbes in the large intestine break down complex carbohydrates and fibers into VFAs, gases, and other byproducts.
3. **Hindgut fermenters (e.g., horses, rabbits): Fermentation mainly occurs in the large intestine, particularly in the cecum and colon. Similar to monogastric animals, hindgut fermenters rely on microbial fermentation in the hindgut to break down fibrous plant material and extract nutrients. The cecum and colon house a diverse microbial population responsible for fermenting cellulose, hemicellulose, and other complex carbohydrates into VFAs, gases, and microbial protein.

The stomach produces hydrochloric acid, pepsin and mucus. Describe the function of each of these secretions.

1. Hydrochloric acid (HCl):
- Creates an acidic environment (pH around 1.5 to 3.5) in the stomach, which is essential for activating pepsinogen to pepsin and for optimal enzymatic activity.
- Denatures proteins by unfolding their three-dimensional structure, making them more accessible to digestive enzymes.
- Helps kill ingested bacteria and other pathogens, aiding in the sterilization of food.
- Facilitates the breakdown of connective tissues and muscle fibers in food, aiding in digestion.
2. Pepsin:
- Pepsin is an enzyme produced by the chief cells in the stomach in an inactive form called pepsinogen. When exposed to the acidic environment of the stomach, pepsinogen is converted into its active form, pepsin.
- Pepsin breaks down proteins into smaller peptides by cleaving peptide bonds between amino acids. This process is known as proteolysis or protein digestion.
- Initiates the digestion of dietary proteins into smaller fragments, preparing them for further breakdown by pancreatic enzymes in the small intestine.
3. Mucus:
- Mucus is produced by goblet cells and mucous cells in the stomach lining and serves several important functions:
- Forms a protective layer that coats the stomach lining, preventing damage from the acidic environment and digestive enzymes.
- Lubricates the stomach wall, allowing food to move smoothly and preventing friction-related injury.
- Acts as a barrier between the stomach epithelium and the acidic gastric juice, preventing self-digestion (autodigestion) of the stomach lining.
- Helps maintain the integrity of the gastric mucosa and promotes healing of any minor injuries or irritations.

What are the accessory organs of the digestive tract? Describe how they assist digestion.

1. Liver: Produces bile, a digestive juice that emulsifies fats, breaking them down into smaller droplets to increase their surface area. This emulsification process facilitates the action of pancreatic lipase, aiding in the digestion and absorption of fats. Stores and concentrates bile between meals in the gallbladder. Detoxifies harmful substances and metabolizes drugs. Stores glycogen, synthesizes proteins, and performs various metabolic functions.
2. Gallbladder: Stores and concentrates bile produced by the liver. Releases bile into the small intestine (duodenum) in response to the presence of fatty foods. Bile aids in the emulsification and digestion of fats.
3. Pancreas: Produces pancreatic juice containing digestive enzymes (amylase, lipase, and proteases) and bicarbonate ions. Amylase breaks down carbohydrates (starches) into maltose and other simple sugars.
Lipase digests fats into fatty acids and glycerol.
Proteases (e.g., trypsin, chymotrypsin) break down proteins into smaller peptides and amino acids.
Bicarbonate ions neutralize the acidic chyme from the stomach, creating an optimal pH environment for pancreatic enzymes to function. Secretes insulin and glucagon into the bloodstream to regulate blood sugar levels.
4. Salivary Glands: Produce saliva containing enzymes (amylase) that initiate the breakdown of carbohydrates (starches) into simpler sugars (maltose). Moistens food to facilitate swallowing and bolus formation. Contains mucin, which lubricates food for easier passage through the esophagus. Helps maintain oral hygiene by flushing away food particles and bacteria.

Identify and describe the function of the crop, proventriculus, and gizzard in the chicken.

1. Crop:
Location: The crop is a sac-like structure located at the base of the esophagus in the chicken's neck region.
Function: The crop acts as a temporary storage pouch for ingested food (feed) before it enters the rest of the digestive system. It allows the chicken to quickly consume a large amount of food and then process it gradually as needed. Food stored in the crop undergoes initial moistening and softening, facilitated by saliva and other ingested fluids, making it easier to swallow and digest.
2. Proventriculus (also known as the glandular stomach):**
Location: The proventriculus is situated between the crop and the gizzard in the chicken's digestive tract.
Function: The proventriculus secretes gastric juices containing hydrochloric acid and digestive enzymes (such as pepsin) that initiate the chemical breakdown of food. It plays a role in the digestion of proteins, breaking them down into smaller peptides and amino acids. The acidic environment in the proventriculus helps to sterilize ingested food, killing potential pathogens and aiding in food safety.
3. Gizzard:
Location: The gizzard is a muscular organ located between the proventriculus and the small intestine.
Function: The gizzard acts as a grinding and mixing chamber, mechanically breaking down ingested food into smaller particles. It contains powerful muscles that contract and grind food with the help of small stones or grit ingested by the chicken. These stones assist in breaking down tough food items such as seeds, grains, and plant material. Once food is sufficiently ground in the gizzard, it passes into the small intestine for further digestion and absorption of nutrients.

What is the relationship between microbiota and host?

The relationship between microbiota and the host organism, often referred to as the microbiota-host interaction, is a dynamic and complex symbiotic relationship. Microbiota refers to the diverse community of microorganisms, including bacteria, fungi, viruses, and archaea, that inhabit various niches within the host organism, such as the skin, gastrointestinal tract, and mucosal surfaces.

How do microbial populations differ in different regions of the gastrointestinal tract? Over the lifetime of an animal?

1. Regional Differences:
- Stomach: The stomach generally harbors fewer microbial populations due to its acidic environment, which limits microbial growth. However, certain bacteria, such as Helicobacter pylori, can colonize the stomach lining.
- Small Intestine: Microbial populations in the small intestine are less abundant compared to the large intestine. The small intestine contains a diverse array of microbes, but their numbers are lower due to the rapid transit of food and the antimicrobial properties of bile and pancreatic secretions.
- Large Intestine (Colon): The colon hosts the highest density and diversity of microbes in the GI tract. Bacteria dominate here, with Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria being the major phyla. These microbes play critical roles in digestion, vitamin synthesis, and immune system development.

Pt.2

2. Changes Over Time (Across the Animal's Lifetime):
- Infancy and Early Development: Microbial colonization of the GI tract begins at birth and is influenced by factors such as mode of delivery (vaginal birth or cesarean section), feeding practices (breastfeeding or formula feeding), and environmental exposures. The gut microbiota undergoes significant development during early life, which can impact the maturation of the immune system and overall health.
- Adulthood: Once established, the composition of the gut microbiota tends to remain relatively stable during adulthood. However, various factors such as diet, medications (e.g., antibiotics), stress, and lifestyle can influence microbial composition.
- Aging: In older age, the gut microbiota may undergo alterations in composition and diversity, which can be influenced by age-related changes in physiology, diet, and health status. These changes may contribute to conditions such as inflammation, metabolic disorders, and susceptibility to infections.

What affects microbes in the gastrointestinal tract?

Diet: Different types of food and dietary patterns can significantly impact the composition and diversity of gut microbiota. For example, diets rich in fiber tend to promote the growth of beneficial bacteria, while diets high in sugar or fat can favor the growth of less desirable microbes.
Medications: Certain medications, particularly antibiotics, can alter the balance of gut microbiota by killing or inhibiting the growth of specific bacterial species. Other medications such as proton pump inhibitors, nonsteroidal anti-inflammatory drugs (NSAIDs), and laxatives can also affect the gut microbiota.
Stress: Psychological stress can impact the gut microbiota through various pathways, including alterations in gut motility, immune function, and hormone levels. Chronic stress has been associated with changes in gut microbial composition and increased susceptibility to gastrointestinal disorders.
Age: The composition of gut microbiota changes over the lifespan, with distinct microbial profiles associated with different age groups. Factors such as diet, lifestyle, and immune function can influence these age-related changes.
Host Genetics: Host genetics can play a role in determining the composition of gut microbiota to some extent. Certain genetic variations have been linked to differences in microbial diversity and susceptibility to specific diseases.

Pt. 2

Environmental Exposures: Environmental factors such as pollution, toxins, and microbial pathogens can impact the gut microbiota. Exposure to pollutants and pathogens can disrupt microbial communities and contribute to gastrointestinal problems.
Lifestyle Factors: Various lifestyle factors including exercise, sleep patterns, smoking, and alcohol consumption can affect the gut microbiota. Healthy lifestyle habits are generally associated with a more diverse and stable microbiota, while unhealthy habits can disrupt microbial balance.
Infections and Diseases: Infections and certain diseases, such as inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS), can lead to alterations in gut microbiota composition and function. Conversely, dysbiosis (imbalanced microbiota) may contribute to the development or exacerbation of these conditions.

What are the functions of carbohydrates in a plant?

1. Energy Storage: Plants store energy in the form of carbohydrates, primarily as starch in specialized storage organs such as roots (e.g., potatoes) and seeds (e.g., grains). Starch serves as a reserve energy source for plants during periods of low photosynthetic activity or growth.
2. Structural Support: Carbohydrates play a crucial role in providing structural support to plant cells and tissues. Cellulose, a complex carbohydrate found in the cell walls of plants, forms a rigid structural framework that maintains cell shape and provides mechanical support to the plant.
3. Photosynthesis: Carbohydrates are essential for photosynthesis, the process by which plants capture light energy and convert it into chemical energy in the form of glucose. Glucose and other simple sugars produced during photosynthesis serve as building blocks for the synthesis of more complex carbohydrates, such as starch and cellulose.
4. Transportation: Plants transport carbohydrates, particularly sucrose, from photosynthetic tissues (e.g., leaves) to non-photosynthetic organs (e.g., roots, fruits, and seeds) for energy storage and growth. Phloem, specialized vascular tissue in plants, facilitates the long-distance transport of carbohydrates throughout the plant.

In an animal?

1. Energy Source: Carbohydrates are the primary source of energy for animals. Glucose, the simplest form of carbohydrate, is readily metabolized by cells to produce ATP (adenosine triphosphate), the universal energy currency of cells. Animals obtain carbohydrates from dietary sources such as sugars, starches, and fiber.
2. Energy Storage: Animals store excess carbohydrates as glycogen, a branched polysaccharide, primarily in the liver and muscles. Glycogen serves as a readily available energy reserve that can be rapidly mobilized to meet the body's energy needs during periods of fasting or increased physical activity.
3. Structural Support: Carbohydrates contribute to the structural integrity of certain tissues in animals. For example, chitin, a complex carbohydrate found in the exoskeletons of arthropods (e.g., insects, crustaceans) and the cell walls of fungi, provides support and protection.
4. Cellular Communication: Carbohydrates play a role in cell-cell recognition and communication in animals. Glycoproteins and glycolipids, molecules consisting of carbohydrates covalently attached to proteins or lipids, are involved in cell surface recognition, immune responses, and signal transduction processes.

How do glycogen, starch and cellulose differ?

1. Structure
- Glycogen: Glycogen is a highly branched polysaccharide consisting of glucose units linked together by α-1,4-glycosidic bonds with α-1,6-glycosidic bonds forming branch points.
- Starch: Starch is also a polysaccharide of glucose, but it may exist in two forms: amylose and amylopectin. Amylose is a linear polymer of glucose linked by α-1,4-glycosidic bonds, while amylopectin is highly branched, similar to glycogen but with fewer branches.
- Cellulose: Cellulose is a linear polysaccharide consisting of β-D-glucose units linked by β-1,4-glycosidic bonds. Unlike glycogen and starch, cellulose does not have branches.
2. Function
- Glycogen: Glycogen serves as the primary energy storage molecule in animals, particularly in the liver and muscles. It is readily broken down into glucose units to provide energy during periods of fasting or increased energy demand.
- Starch: Starch functions as the main energy storage molecule in plants, stored in specialized storage organs such as roots, tubers, and seeds. It serves as a readily available energy source for plant growth and metabolism.
- Cellulose: Cellulose provides structural support to plant cell walls, contributing to their rigidity and strength. It serves as a structural component in plant tissues, aiding in growth, support, and protection.
3. Digestibility:
- Glycogen and Starch: Both glycogen and starch are readily digestible by animals, as they are composed of α-glucose units linked by α-1,4-glycosidic bonds and, in the case of starch, α-1,6-glycosidic bonds in amylopectin. Enzymes such as amylase hydrolyze these bonds, breaking down glycogen and starch into glucose for energy.
- Cellulose: Cellulose is indigestible by most animals due to the β-1,4-glycosidic bonds, which cannot be broken down by the enzymes produced by animals. However, some anima

How are they the same?

1. Composition: All three carbohydrates are composed of glucose monomers linked together by glycosidic bonds.
2. Polysaccharides: Glycogen, starch, and cellulose are all polysaccharides, meaning they consist of long chains of repeating sugar units.
3. Biological Importance: They are all biologically significant molecules involved in energy storage (glycogen and starch) or structural support (cellulose) in organisms.
4. Alpha and Beta Glycosidic Bonds: While the type of glycosidic bond differs between cellulose (β-1,4) and glycogen/starch (α-1,4 and α-1,6), they share the general concept of glycosidic bond formation, where glucose units are linked together.

Which type of carbohydrates are absorbed? Where?

Glucose and galactose are absorbed into the epithelial cells lining the small intestine through a process called active transport. Fructose is absorbed into the epithelial cells of the small intestine through facilitated diffusion, rather than active transport.

Define metabolism.

Metabolism refers to the sum total of all biochemical reactions that occur within an organism to maintain life. These reactions involve the conversion of molecules (substrates) into different forms, resulting in the production of energy, building blocks for cellular structures, and molecules necessary for various physiological processes. Metabolism can be broadly categorized into two main types of processes: Catabolism and Anabolism

Where are carbohydrates stored in an animal body? In what form?

Carbohydrates are primarily stored in the form of glycogen in animal bodies. Glycogen is a polysaccharide composed of glucose molecules linked together in a branched structure. It serves as a readily mobilizable energy reserve, particularly in the liver and muscles.
1. Liver: The liver is a major site of glycogen storage in animals. Liver glycogen serves as a source of glucose for maintaining blood glucose levels during fasting periods or times of increased energy demand. When blood glucose levels decrease, glycogen stored in the liver is broken down into glucose and released into the bloodstream to maintain glucose homeostasis.
2. Muscles: Skeletal muscles also store significant amounts of glycogen, though the total glycogen content in muscle is generally higher in animals with greater muscle mass. Muscle glycogen serves as a localized energy reserve, providing glucose for muscle contraction during exercise or periods of increased physical activity. Muscle glycogen is primarily used to fuel muscle metabolism and is not readily released into the bloodstream like liver glycogen.

1. Define the metabolic pathways below:
a. Glycolysis
b. Glycogenesis and Glycogenolysis
c. TCA, Citric acid cycle, or Krebs cycle
d. Oxidative phosphorylation
e. Gluconeogenesis

Glycolysis: A metabolic pathway that occurs in the cytoplasm of cells and involves the breakdown of glucose (a six-carbon sugar molecule) into two molecules of pyruvate (a three-carbon compound). This process occurs in multiple enzymatic steps and generates ATP (adenosine triphosphate) and NADH (nicotinamide adenine dinucleotide) as energy carriers. Glycolysis is the first stage of cellular respiration and can occur under both aerobic and anaerobic conditions.
Glycogenesis: The process of synthesizing glycogen, a branched polysaccharide composed of glucose molecules, primarily occurring in the liver and muscles. During glycogenesis, glucose molecules are added to a growing glycogen chain through the action of the enzyme glycogen synthase. This process allows for the storage of excess glucose for later use.
Glycogenolysis: The breakdown of glycogen into glucose-1-phosphate, which can then be converted into glucose-6-phosphate and enter glycolysis for energy production. This process occurs primarily in the liver and muscles and is stimulated by hormones such as glucagon and adrenaline during periods of low blood glucose levels, providing a rapid source of glucose for energy production.
TCA Cycle (Citric Acid Cycle or Krebs Cycle): A series of enzymatic reactions that occur in the mitochondrial matrix of eukaryotic cells and the cytoplasm of prokaryotic cells. The TCA cycle completes the oxidation of acetyl-CoA (a two-carbon molecule derived from the breakdown of carbohydrates, fats, and proteins) to produce ATP, NADH, FADH2, and carbon dioxide (CO2). These energy carriers (NADH and FADH2) generated during the TCA cycle feed into the electron transport chain for oxidative phosphorylation.
Oxidative Phosphorylation: The final stage of cellular respiration that occurs in the inner mitochondrial membrane of eukaryotic cells

Describe the enzymatic digestion of sucrose, starch and cellulose. Where does this happen? How?

Enzymatic digestion of carbohydrates such as sucrose, starch, and cellulose occurs primarily in the gastrointestinal tract, specifically in the mouth, stomach, and small intestine. Different enzymes are involved in the breakdown of these carbohydrates into smaller, absorbable molecules.

What are VFA's? What are they used for?

VFA stands for Volatile Fatty Acids. These are a group of organic compounds that are produced by the microbial fermentation of organic matter in various environments, including the digestive systems of animals (such as cows, sheep, and goats) and in anaerobic digesters used for wastewater treatment or biogas production.
In animal digestion, VFAs are primarily produced in the rumen, the largest compartment of the stomach, through microbial fermentation of ingested plant material. The main VFAs produced in the rumen are acetic acid, propionic acid, and butyric acid. These VFAs are important energy sources for the animal, as they can be absorbed through the rumen wall and used as substrates for energy metabolism.

How do insulin and glucagon influence blood glucose levels? Where are these hormones produced?

I. Insulin: Insulin is produced by the beta cells of the pancreas, specifically in the islets of Langerhans. Its primary function is to lower blood glucose levels by promoting the uptake of glucose into cells, where it can be used for energy production or stored for later use. Insulin also stimulates the liver and muscle cells to store excess glucose in the form of glycogen, which helps to further decrease blood glucose levels. Additionally, insulin inhibits the breakdown of fats and proteins, promoting their storage instead.
2. Glucagon: Glucagon, on the other hand, is produced by the alpha cells of the pancreas, also in the islets of Langerhans. Its main role is to raise blood glucose levels when they fall too low. Glucagon stimulates the liver to break down glycogen into glucose through a process called glycogenolysis. It also promotes gluconeogenesis, which is the synthesis of glucose from non-carbohydrate sources such as amino acids and glycerol. These actions of glucagon help to release glucose into the bloodstream, thereby increasing blood glucose levels.

What are the 10 essential amino acids required by animals? Which extra amino acid do cats require?

Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
Arginine
Cats: Taurine

Describe the four layers of protein structure. How does the process of denaturation and enzymatic digestion alter protein structure?

The primary structure of a protein refers to the linear sequence of amino acids that make up the polypeptide chain.
Secondary structure refers to the local folding patterns that occur within the polypeptide chain. The two most common types of secondary structure are alpha helices and beta sheets.
Tertiary structure refers to the three-dimensional arrangement of the entire polypeptide chain.
Quaternary structure refers to the arrangement of multiple polypeptide chains (subunits) that come together to form a functional protein complex
Denaturation is the process by which a protein loses its native structure and function due to external stressors such as heat, pH changes, or exposure to certain chemicals.
Enzymatic digestion involves the breakdown of proteins into smaller peptides and individual amino acids by proteolytic enzymes such as pepsin, trypsin, and chymotrypsin.

Describe protein catabolism and synthesis within an animal.

Protein catabolism involves the breakdown of proteins into their constituent amino acids or smaller peptide fragments. This process occurs through several steps: Digestion, Absorption, Transport, Catabolic Pathways, Energy Production.
Protein synthesis is the process by which cells build new proteins using amino acids. It involves several steps: Transcription, Translation, Post-translational Modifications

How is protein metabolism connected to carbohydrate metabolism?

Protein metabolism and carbohydrate metabolism are interconnected through various metabolic pathways and processes within the body. Here are some key connections between the two: Gluconeogenesis, Glycolysis, Citric Acid Cycle (Krebs Cycle), Energy Production, Regulation of Blood Glucose Levels

Compare the amount of energy contained in carbohydrates, lipids, and proteins.

Carbohydrates are the body's primary source of energy. They provide approximately 4 calories per gram.
Lipids, including both fats and oils, are a concentrated source of energy. They provide approximately 9 calories per gram, more than twice the energy content of carbohydrates or proteins.
Proteins are primarily involved in building and repairing tissues, enzymes, hormones, and other essential molecules in the body.

Define saturated, unsaturated, polyunsaturated fatty acids, and triacylglycerols

Saturated fatty acids are a type of fatty acid in which the carbon atoms are bonded to as many hydrogen atoms as possible, resulting in a straight, rigid molecular structure with no double bonds between carbon atoms.
Unsaturated fatty acids are fatty acids that contain one or more double bonds between carbon atoms in the hydrocarbon chain. The presence of double bonds creates kinks or bends in the molecular structure, preventing the fatty acids from packing tightly together.
Polyunsaturated fatty acids have two or more double bonds in the hydrocarbon chain. Examples include linoleic acid (omega-6 fatty acid) and alpha-linolenic acid (omega-3 fatty acid), both of which are essential fatty acids that must be obtained from the diet since the body cannot synthesize them.
Triacylglycerols, also known as triglycerides, are the main form of dietary fat and the primary storage form of fat in the body. They consist of three fatty acid molecules esterified to a glycerol molecule.

What are the functions of lipids in animal bodies?

Cell Membrane Structure
Energy Storage
Insulation and Thermal Regulation
Insulation and Thermal Regulation
Protection and Cushioning
Hormone Production
Cell Signaling and Communication
Absorption of Fat-Soluble Vitamins

How does bile enhance lipid digestion? Where is this made?

Bile enhances lipid digestion by aiding in the emulsification and solubilization of dietary fats. Bile is a greenish-yellow fluid that is produced by the liver and stored and concentrated in the gallbladder before being released into the small intestine.

Describe the activity of pancreatic lipase. What is a micelle? How are lipids absorbed across intestinal cells?

Pancreatic lipase plays a crucial role in the digestion of dietary fats by hydrolyzing triglycerides into fatty acids and monoglycerides. These lipid digestion products are then solubilized in micelles, absorbed across the intestinal cells, and transported in chylomicrons to tissues throughout the body.
Lipids are absorbed across intestinal cells (enterocytes) through a process that involves the formation of micelles, passive diffusion or facilitated transport of lipid digestion products across the apical membrane of enterocytes, intracellular processing, and the formation of chylomicrons for transport.

How do hydrophobic lipids travel through the blood?

Hydrophobic lipids, such as triglycerides and cholesterol esters, are insoluble in water and therefore cannot dissolve directly in the aqueous environment of the bloodstream. Instead, hydrophobic lipids travel through the blood by being packaged into lipoprotein particles. Lipoproteins are complex structures composed of a core of hydrophobic lipids surrounded by a shell of amphipathic molecules, including phospholipids, cholesterol, and proteins called apolipoproteins.

Where is lipoprotein lipase located in the body? What does it do?

Lipoprotein lipase (LPL) is primarily located on the surface of cells lining the capillaries in various tissues throughout the body, including adipose tissue, muscle tissue, and cardiac muscle tissue. It is especially abundant in tissues with high metabolic activity and high energy demands, such as skeletal muscle and adipose tissue.
Function: Lipid Hydrolysis, Release of Free Fatty Acids, Regulation of Lipid Storage and Distribution