biology exam 4

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I. Circulatory System

A. List 6 basic functions of a circulatory system:

1. 2. 3. 4. 5. 6. Transport of gases: Oxygen and carbon dioxide are transported to and from tissues.

Nutrient delivery: Nutrients from digestion (like glucose) are transported to cells.

Waste removal: Removes metabolic waste products (e.g., urea) for excretion.

Immune defense: White blood cells (WBCs) help fight infections.

Hormone transport: Hormones are transported to target organs.

Thermoregulation: Helps in maintaining body temperature by distributing heat.

II. Types of Internal Transport Systems

A. No true circulatory system:

● Organisms like sponges, cnidarians, and flatworms lack a true circulatory system.

They rely on diffusion for transport of gases, nutrients, and waste.

B. Open Circulatory System:

1. 2. 3. Definition: A system where blood is not entirely enclosed in vessels; it bathes organs

directly.

Components of an open system:

○ Hemolymph (analogous to blood) is pumped through body cavities and

surrounding organs.

○ Hemocoel: A body cavity that contains the hemolymph and surrounds the

organs.

3 characteristics of an open system:

○ Low pressure: Blood flows slowly and with lower pressure.

○ Less efficient transport: Nutrient and gas exchange is slower compared to

closed systems.

○ Limited control over flow: Blood can flow freely between vessels and tissues.

C. Closed Circulatory System:

1. Definition: A system where blood is contained within blood vessels and circulates

through the body.

○ Artery: Carries blood away from the heart; thick-walled and elastic.2. ○ Vein: Carries blood towards the heart; thinner-walled, with valves to prevent

backflow.

○ Capillary: Microscopic vessels where gas and nutrient exchange occurs.

3 characteristics of a closed system:

○ Higher pressure: Blood is under higher pressure, ensuring quicker circulation.

○ Efficient transport: Blood can be directed precisely to different body regions.

○ Better control: The circulatory flow can be regulated via vessel

constriction/relaxation.

D. Vertebrate Cardiovascular Systems

1. Single circuit circulatory system:

○ Example: Found in fish. Blood flows from the heart to the gills (for oxygenation),

and then directly to the body tissues in one continuous loop.

2. Double circuit circulatory system:

○ Example: Found in amphibians, reptiles, birds, and mammals. There are two

loops:

1. Pulmonary circuit: Blood is pumped from the heart to the lungs for

2. oxygenation.

Systemic circuit: Oxygenated blood is then pumped from the heart to

the rest of the body.

Drawing of Human Circulation Pattern:

You should include a diagram showing the heart, pulmonary circulation, and systemic

circulation, emphasizing the flow of oxygenated and deoxygenated blood through the heart,

lungs, and body.

III. The Heart

A. Size:

● About the size of a fist (roughly 12 cm x 8 cm).

B. Location:

● The heart is located in the thoracic cavity, between the lungs, slightly to the left.

Pericardium:● A double-walled membrane surrounding the heart that provides protection and reduces

friction.

C. 4 chambers of the human heart:

1. Right Atrium:

○ Function: Receives deoxygenated blood from the body (via the superior and

inferior vena cava).

2. Right Ventricle:

○ Function: Pumps deoxygenated blood to the lungs through the pulmonary artery.

3. Left Atrium:

○ Function: Receives oxygenated blood from the lungs via the pulmonary veins.

4. Left Ventricle:

○ Function: Pumps oxygenated blood to the entire body through the aorta.

D. Rhythmic cycle of the heart:

1. 2. 3. Cardiac cycle: The series of events that occurs when the heart contracts and relaxes

(systole and diastole).

Diastole: The relaxation phase, where the heart chambers fill with blood.

Systole: The contraction phase, where the heart pumps blood out of the chambers.

IV. Blood Pressure

A.

● Blood pressure refers to the force exerted by the blood on the walls of blood vessels,

especially the arteries.

1. 2. Systolic pressure: Pressure when the heart contracts.

Diastolic pressure: Pressure when the heart is at rest between beats.

B. Measurement of blood pressure:

● Average blood pressure for a young adult: 120/80 mmHg.

C. Pulse:

● The rhythmic expansion and contraction of the arteries due to the heartbeat; can be felt

at pulse points (e.g., wrist, neck).V. Heart Attack

A. Coronary arteries:

● These are the blood vessels that supply oxygenated blood to the heart muscle itself.

Heart attack (Myocardial infarction):

● Occurs when a blockage in the coronary arteries cuts off blood flow to part of the heart

muscle, causing damage.

Possible treatments for coronary artery buildup:

● Angioplasty: A procedure to open up blocked arteries using a balloon.

● Stents: Small tubes inserted to keep arteries open.

● Bypass surgery: Reroutes blood flow around blocked arteries.

VII. Blood

A. Approximately 5 liters of blood in adult humans.

B. Non-cellular components:

1. Plasma:

○ The liquid portion of blood, consisting mostly of water, electrolytes, proteins, and

waste products.

2. a. Function: Transports nutrients, gases, hormones, and waste products. b.

Components:

○ Water (about 90%)

○ Proteins (e.g., albumin, fibrinogen)

○ Nutrients (e.g., glucose, vitamins)

○ Waste products (e.g., urea)

○ Electrolytes (e.g., sodium, potassium)

C. Cellular Components (45% of blood):

1. 2. Erythrocytes (Red Blood Cells, RBC):

○ Normal count: 4.5 to 6 million cells per microliter.

○ Major function: Transport oxygen from the lungs to tissues and carbon dioxide

back to the lungs.

○ Average lifespan: 120 days.

○ Anemia: A condition where there are too few red blood cells or they do not

function properly, resulting in insufficient oxygen delivery.

Leukocytes (White Blood Cells, WBC):○ Normal count: 4,000 to 11,000 cells per microliter.

○ Major function: Part of the immune system, defending the body against

infections and foreign invaders.

3. Thrombocytes (Platelets):

○ Normal count: 150,000 to 450,000 per microliter.

○ Major function: Blood clotting; helps form blood clots to stop bleeding.

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I. Digestion

Mechanical Digestion

● Definition: The physical breakdown of food into smaller pieces without changing the

chemical structure. Examples: chewing food (mastication), churning of food in the

stomach.

Chemical Digestion

● Definition: The breakdown of food into simpler molecules through chemical reactions,

typically using enzymes and acids. Examples: enzymatic breakdown of proteins,

carbohydrates, and fats.

II. 5 Stages of Food Processing

1. Ingestion

○ The intake of food into the mouth.

2. Transport & Temporary Storage

○ Movement of food through the digestive tract and temporary storage, primarily in

the stomach and intestines.

3. Digestion

○ The breakdown of food into absorbable components (chemical and mechanical

digestion).

4. Absorption

○ Nutrients from digested food are absorbed into the bloodstream or lymphatic

system, mainly in the small intestine.

5. Elimination

○ The removal of undigested and unabsorbed materials from the body in the form

of feces.

III. Intracellular vs Extracellular Digestion

Intracellular Digestion

● Definition: Digestion that occurs inside the cells, where food is engulfed by

phagocytosis and broken down by enzymes within vacuoles. Found in simpler organisms

like sponges, protists, and some invertebrates.

Extracellular Digestion● Definition: Digestion that occurs outside the cell, in a digestive cavity or tract. In

humans and most complex animals, food is broken down in the stomach and intestines

by enzymes.

Drawing of Simple Extracellular Digestion:

1. 2. 3. 4. Step 1: Food enters through the mouth.

Step 2: Digestion starts in the stomach and small intestine with enzymes.

Step 3: Nutrients are absorbed into the bloodstream.

Step 4: Undigested materials are eliminated through the rectum and anus.

IV. Major Components of the Human Digestive System

● Route Through – Continuous Tube:

Oral cavity → Pharynx → Esophagus → Stomach → Small intestine → Large intestine

→ Rectum → Anus.

Oral Cavity:

1. Saliva:

○ Four ways that saliva is important in food processing:

■ a. Moistens food to facilitate swallowing.

■ b. Contains enzymes (like amylase) that start chemical digestion of

carbohydrates.

■ c. Helps neutralize acids in the mouth, protecting teeth.

■ d. Provides antimicrobial agents to help control bacteria.

2. Teeth:

○ Mastication: The process of chewing food to break it down into smaller pieces.

○ Two reasons for chewing your food before swallowing:

■ 1) It increases the surface area of food, aiding digestion.

■ 2) It makes swallowing easier and prevents choking.

3. Tongue – 3 main functions:

○ a. Helps move food around the mouth for chewing and swallowing.

○ b. Helps form the bolus (chewed food) for swallowing.

○ **c. Taste buds: Detect flavor and send signals to the brain about taste.

○ NOTE: Flavor = T aste + smell.

4. Oral Pharynx:

○ a. Swallowing:

■ 1) Involves the coordinated movement of the tongue, soft palate, and

throat muscles.

■ a) Bolus: A ball of chewed food that is pushed to the back of the mouth

for swallowing.5. ■ 2) NOTE: As you swallow, the epiglottis ("voice box") moves upward

causing the glottis to close, blocking the trachea to prevent choking.

Digestion in the Oral Cavity:

○ a. Mechanical digestion: Chewing (mastication) breaks food into smaller

pieces.

○ b. Chemical digestion: Salivary amylase begins the breakdown of starches.

C. Esophagus

1. Peristalsis:

○ a. Definition: The wave-like muscle contractions that move food down the

esophagus.

○ b. Function: Helps transport the bolus from the mouth to the stomach.

D. Stomach (Approximately 4 hours)

1. 2. Function: Mechanical and chemical digestion of food, especially proteins.

Chyme: The partially digested food and gastric juices mixture.

3. Ulcers:

4. ○ a. Gastric Ulcers: Sores on the stomach lining caused by the erosion due to

stomach acid or bacterial infection (Helicobacter pylori).

Summarize Digestion in the Stomach:

○ a. Mechanical digestion: Stomach muscles churn food to mix with gastric

juices.

○ b. Chemical digestion: Pepsin (an enzyme) breaks down proteins; hydrochloric

acid activates enzymes and kills bacteria.

E. Small Intestine (20-25 feet in length; food remains here approx. 6 hours)

1. 3 Regions:

○ a. Duodenum (10 inches):

■ 1) Receives bile from the liver and pancreatic enzymes to help digest fats,

proteins, and carbohydrates.

■ 2) Most chemical digestion occurs here.

■ 3) Involves neutralizing stomach acid.

■ 4) Enzymes from the pancreas and liver aid digestion.

○ b. Jejunum (8 feet in length):

■ 1) Main site of nutrient absorption (e.g., amino acids, sugars, fats).

○ c. Ileum (12 feet in length):

■ 1) Absorbs remaining nutrients (especially vitamin B12 and bile salts).■ a) Villi and Microvilli:

■ Small hair-like structures in the small intestine that increase

surface area for absorption.

2. Functions of Associated Organs:

○ a. Pancreas:

■ 1) Produces digestive enzymes (lipase, amylase, trypsin).

■ 2) Secretes bicarbonate to neutralize stomach acid.

○ b. Liver:

■ 1) Produces bile for fat emulsification.

■ 2) Detoxifies harmful substances.

■ 3) Stores glucose as glycogen.

■ 4) Metabolizes nutrients.

■ 5) Regulates cholesterol levels.

■ 6) Produces plasma proteins like albumin and clotting factors.

3. Summarize Digestion in the Small Intestine:

○ a. Mechanical digestion: Churning and segmentation of food to aid absorption.

○ b. Chemical digestion: Enzymes from the pancreas, bile from the liver break

down fats, proteins, and carbohydrates.

E. Large Intestine or Colon (5 feet in length; 12-24 hours)

1. Cecum or Appendix at the junction of the small and large intestine (right side).

○ a. Appendix: Plays a minor role in immunity, but its exact function is not fully

understood.

2. Function of the Large Intestine:

○ Absorbs water, salts, and some vitamins.

○ Forms and stores feces.

3. Feces:

○ a. Water (about 75%).

○ b. Indigestible food particles (e.g., fiber).

○ c. Bacteria (gut flora).

○ d. Dead cells from the lining of the intestines.

○ e. Salts and metabolic waste products.

○ f. Mucus.

4. Rectum:

○ Stores feces until they are excreted.

5. Anus:

6. ○ The opening where feces are expelled from the body.

Summarize Digestion in the Large Intestine:

○ a. Absorption of water and electrolytes (salts) from indigestible food.

○ b. Formation of solid waste (feces).

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I. Introduction to the Respiratory System

Human body cells use oxygen and produce carbon dioxide.

Example:

● Oxygen is used in cellular respiration to produce ATP (energy).

● Carbon dioxide is produced as a waste product of cellular metabolism.

Gas exchange:

● The process where oxygen moves from the lungs into the blood, and carbon dioxide

moves from the blood into the lungs to be exhaled.

C. 3 Phases of Gas Exchange

1. Breathing:

○ Inhaling: T aking in oxygen-rich air from the environment into the lungs.

○ Exhaling: Releasing carbon dioxide-rich air from the lungs into the environment.

2. Transport of Gases by the Circulatory System:

○ a. Oxygen is carried by hemoglobin in red blood cells from the lungs to body

tissues.

○ b. Carbon dioxide is carried from tissues to the lungs, where it is expelled.

○ c. Gases dissolve in the blood plasma (a small portion of oxygen and carbon

dioxide are transported dissolved in plasma).

3. Cells take up oxygen from the blood and give up carbon dioxide to the blood in

tissues during respiration.

D. The Exchange of Oxygen and Carbon Dioxide

1. Respiratory Surface:

○ The thin, moist surface where gas exchange occurs, typically found in the alveoli

of the lungs.

2. Characteristics of respiratory surfaces:

○ a. Thin: So gases can diffuse easily (e.g., one cell layer thick in the alveoli).

○ b. Moist: Gases must dissolve in water to diffuse across the membrane.

○ c. Large surface area: Provides more space for gas exchange (e.g., millions of

alveoli).II. Human Gas Exchange System

Route Through Respiratory System (inhalation – reverse for exhalation):

1. Nostrils/Nares

2. Nasal cavity

3. Oral pharynx

4. Larynx (voice box)

5. Trachea (windpipe)

6. Bronchi

7. Bronchioles

8. Alveoli (air sacs)

B. Nostrils or Nares:

● The external openings of the nose through which air enters and exits the respiratory

system.

C. Functions of the Nasal Cavity/Passages:

1. 2. 3. 4. Filters air: Nose hairs (cilia) trap dust and pathogens.

Moisturizes air: Mucus lining moistens incoming air, preventing dry air from irritating the

lungs.

Warms air: Blood vessels in the nasal cavity warm the air to body temperature.

Smell: Olfactory receptors in the nasal cavity allow for the sense of smell.

D. Oral Pharynx:

● The part of the throat behind the mouth that connects the nasal cavity to the larynx. It

serves as a passageway for air and food.

1. Function of the soft palate and the uvula:

○ Prevents food and liquid from entering the nasal passages during swallowing.

2. Function of the epiglottis:

○ A flap of tissue that covers the trachea during swallowing to prevent food and

liquids from entering the airways.

E. Larynx or Voice Box:● Located at the top of the trachea, the larynx contains vocal cords, which vibrate to

produce sound when air passes through.

F . Trachea or Windpipe:

● The tube that connects the larynx to the bronchi. It is lined with cilia and mucus to filter

and transport air to the lungs.

1. NOTE: The trachea is reinforced with cartilage rings that keep it open.

G. Bronchi:

● The two main branches of the trachea that lead to each lung. They divide into smaller

bronchioles.

H. Bronchioles:

● Smaller branches of the bronchi that lead to the alveoli. They control airflow to the lungs

and are lined with smooth muscle to regulate airflow.

I. Alveoli:

● Tiny, balloon-like structures at the end of the bronchioles where gas exchange occurs.

Oxygen diffuses into the blood, and carbon dioxide diffuses out to be exhaled.

1. There are millions of alveoli in each lung, which provides a large surface area for gas

exchange.

III. Breathing or Ventilation

A. 2 Types of Breathing:

1. Positive Pressure Breathing:

frogs).

2. Negative Pressure Breathing:

○ Air is forced into the lungs by increasing pressure, as seen in amphibians (e.g.,○ Air is drawn into the lungs by creating a lower pressure inside the chest cavity

compared to the outside atmosphere. This is how humans and most mammals

breathe.

B. Mechanism of Inhalation:

1. 2. 3. Diaphragm contracts and moves downward, increasing the volume of the thoracic

cavity.

Intercostal muscles contract, expanding the rib cage.

This increases the volume inside the chest, decreasing pressure, causing air to flow

into the lungs.

C. Mechanism of Exhalation:

1. 2. 3. Diaphragm relaxes and moves upward, decreasing the volume of the thoracic cavity.

Intercostal muscles relax, causing the rib cage to return to its normal position.

This decreases the volume inside the chest, increasing pressure, causing air to be

pushed out of the lungs.

D. Automatic Control of Breathing:

1. 2. Breathing control centers located in the pons and medulla oblongata (medulla) of

the brain.

○ a. Medulla oblongata: Controls the rate of breathing based on blood CO₂ levels.

○ b. Pons: Modulates the rhythm and smooths the transition between inhalation

and exhalation.

Hyperventilation or "Over" or "Too much" breathing:

○ a. Hyperventilation occurs when you breathe rapidly and deeply, reducing CO₂

levels in the blood, which can lead to dizziness or lightheadedness.

IV. Transport of Respiratory Gases

A. Oxygen Transport:

● Oxygen binds to hemoglobin in red blood cells and is transported through the

bloodstream to body tissues.B. Carbon Dioxide Transport:

● Carbon dioxide is transported in three forms:

○ 1. Dissolved in plasma (about 7%).

○ 2. Bound to hemoglobin (about 23%).

○ 3. Converted to bicarbonate ions (about 70%) for transport in the blood.

V. Carbon Monoxide Poisoning

A. Carbon monoxide (CO) is a colorless, odorless gas produced by incomplete combustion.

B. How it works:

● CO binds to hemoglobin more strongly than oxygen, preventing oxygen from binding and

being transported to tissues, leading to hypoxia (lack of oxygen).

C. Treatment:

● High-flow ox

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Cellular Respiration – Energy for Cells

Cellular Respiration:

● Site in Eukaryotic Cells:

○ Mitochondria (mainly in the inner mitochondrial membrane and matrix).

● Importance:

○ Cellular respiration is the process by which cells extract energy from organic

molecules (like glucose) to produce ATP (adenosine triphosphate), which is used

as an energy source for cellular activities.

● ATP:

○ Adenosine Triphosphate (ATP) is the primary energy carrier in cells. ATP is

used in almost every energy-requiring process in a cell, such as active transport,

protein synthesis, and muscle contraction.

Types of Cellular Respiration

1. Aerobic Respiration:

○ Requires oxygen to produce ATP .

○ T akes place in mitochondria and involves three stages: Glycolysis, Krebs

Cycle, and Electron Transport Chain.

○ Produces a large amount of ATP (about 36-38 ATP molecules per glucose

molecule).

2. Anaerobic Respiration:

○ Occurs without oxygen.

○ Less efficient, producing only 2 ATP molecules per glucose.

○ In animals, anaerobic respiration results in lactic acid.

○ In plants and some microorganisms, it results in ethanol (alcohol) and carbon

dioxide.

○ Plants produce: Ethanol and carbon dioxide during anaerobic respiration

(fermentation).

○ Animals produce: Lactic acid (lactic acid fermentation) during anaerobic

respiration.

Aerobic Cellular Respiration

General Equation for Aerobic Cellular Respiration:

Glucose (C₆H₁₂O₆)+Oxygen (O₂)→Carbon dioxide (CO₂)+Water (H₂O)+ATPGlucose

(C₆H₁₂O₆)+Oxygen (O₂)→Carbon dioxide (CO₂)+Water (H₂O)+ATP● This equation shows that glucose and oxygen are used to produce carbon dioxide,

water, and energy (ATP).

Stages of Cellular Respiration

1. Glycolysis (Occurs in the cytoplasm)

○ Inputs:

■ 1 Glucose molecule (C₆H₁₂O₆)

■ 2 NAD⁺ (Nicotinamide adenine dinucleotide)

■ 2 ATP molecules (for activation energy)

○ Outputs:

■ 2 Pyruvate molecules (C₃H₄O₃)

■ 2 NADH (electron carriers)

■ 4 ATP molecules (net gain of 2 ATP)

■ 2 H₂O molecules

○ Summary: Glycolysis is the breakdown of 1 molecule of glucose into 2

molecules of pyruvate, with a small gain of ATP and NADH. It does not require

oxygen and occurs in the cytoplasm.

2. Krebs Cycle (Citric Acid Cycle) (Occurs in the mitochondrial matrix)

○ Inputs:

■ 2 Acetyl CoA (derived from pyruvate)

■ 2 NAD⁺

■ 2 FAD (another electron carrier)

■ 2 ADP + Pi (phosphate)

○ Outputs:

■ 4 CO₂ (carbon dioxide, waste product)

■ 6 NADH (electron carriers)

■ 2 FADH₂ (electron carriers)

■ 2 ATP (direct ATP production)

○ Summary: The Krebs cycle processes the Acetyl CoA produced from glucose

(via pyruvate) and releases carbon dioxide, generating electron carriers (NADH,

FADH₂) and small amounts of ATP .

3. Electron Transport Chain (ETC) (Occurs in the inner mitochondrial membrane)

○ Inputs:

■ 10 NADH (from glycolysis and Krebs cycle)

■ 2 FADH₂ (from Krebs cycle)

■ Oxygen (O₂) (final electron acceptor)■ ADP + Pi (for ATP production)

○ Outputs:

■ ATP (32-34 molecules)

■ Water (H₂O) (formed when electrons combine with oxygen)

○ Summary: The electron transport chain involves the transfer of electrons through

protein complexes in the inner mitochondrial membrane. The energy released is

used to pump protons (H⁺) across the membrane, creating a proton gradient. The

protons flow back through ATP synthase, generating ATP . Oxygen is the final

electron acceptor, forming water.

Total ATP Production from Cellular Respiration

● Aerobic Respiration = 36-38 ATP (depending on the cell type and conditions)

○ Glycolysis: 2 ATP

○ Krebs Cycle: 2 ATP

○ Electron Transport Chain: 32-34 ATP

● Anaerobic Respiration = 2 ATP

○ Only glycolysis is involved, and it produces a net gain of 2 ATP molecules.

Organic Molecules and Energy Sources

● Free glucose molecules are not typically found in large quantities in our diets.

Most carbohydrates are ingested as polysaccharides like starch, which are broken down

into monosaccharides (such as glucose) before they can enter cellular respiration.

A. Carbohydrates:

1. 2. Starch (Polysaccharide) → Glucose (Monosaccharide)

○ Starch is broken down by enzymes like amylase into glucose.

Disaccharides (e.g., sucrose or lactose) → Glucose (Monosaccharide)

○ Disaccharides are hydrolyzed into glucose and other sugars, which can enter

glycolysis.

○ Glucose enters glycolysis to begin cellular respiration.

B. Proteins:

● Proteins → Amino acids○ Proteins are broken down into amino acids, which are then deaminated (removal

of the amino group). The remaining carbon skeletons can enter glycolysis or the

Krebs cycle, depending on their structure.

C. Lipids:

● Lipids → Glycerol and Fatty Acids

○ Lipids are broken down into glycerol and fatty acids.

○ Glycerol enters the middle of glycolysis (can be converted into an

intermediate of glycolysis).

○ Fatty Acids → Acetyl CoA enters the Krebs cycle.

■ Fatty acids undergo beta-oxidation, which breaks them into two-carbon

acetyl groups that enter the Krebs cycle as Acetyl CoA.

NOTE:

● Fatty acids are a high-energy source. Lipids produce much more ATP per molecule

than carbohydrates or proteins due to the larger number of carbons available for

oxidation in the Krebs cycle.

Page 6

1. What happens in cellular respiration?

Cellular respiration is the process by which cells convert glucose (or other organic molecules)

into ATP (energy), which cells use for their metabolic activities. The process involves breaking

down glucose into carbon dioxide, water, and energy (ATP).

2. What are the two types of cellular respiration? How are they different?

● Aerobic Respiration: Requires oxygen and occurs in the mitochondria. It produces

36-38 ATP molecules per glucose.

○ Stages: Glycolysis (cytoplasm), Krebs Cycle (mitochondrial matrix), Electron

Transport Chain (inner mitochondrial membrane).

○ Byproducts: Carbon dioxide (CO₂) and water (H₂O).

● Anaerobic Respiration: Does not require oxygen and occurs in the cytoplasm. It

produces only 2 ATP per glucose.

○ Byproducts: In animals, lactic acid is produced; in yeast/plants, ethanol and CO₂

are produced.

3. Be able to list the four biological macromolecules and their associated

monomers.

● Carbohydrates: Monomer = Monosaccharides (e.g., glucose, fructose)

● Proteins: Monomer = Amino acids

● Lipids: Monomer = Fatty acids and Glycerol

● Nucleic acids: Monomer = Nucleotides (e.g., adenine, thymine, cytosine, guanine,

uracil)

4. What are the two major types of digestion? Give examples.

● Mechanical Digestion: Physically breaking down food into smaller pieces. Example:

Chewing, churning in the stomach.

● Chemical Digestion: Breaking down food molecules into simpler molecules through

enzymatic action. Example: Enzyme activity in the stomach (pepsin) or small intestine

(amylase, lipase).

5. Be able to list the 5 stages of food processing.1. 2. 3. 4. 5. Ingestion: T aking in food.

Transport & Temporary Storage: Moving food to the stomach (e.g., esophagus).

Digestion: Breaking down food into smaller molecules (mechanical & chemical).

Absorption: Nutrients are absorbed into the bloodstream (mainly in the small intestine).

Elimination: Removal of undigested material (feces) through the anus.

6. Differentiate between extracellular and intracellular digestion.

● Intracellular Digestion: Occurs within cells. Example: In sponges and protozoans, food

particles are engulfed by phagocytosis and digested in vacuoles.

● Extracellular Digestion: Occurs outside cells in a digestive cavity (e.g., stomach,

intestines). Example: Humans, where food is broken down in the stomach and small

intestine.

7. Be able to list the route through the human digestive system and explain

what happens in each section, including types of digestion and key

characteristics.

● Mouth: Mechanical digestion (chewing) and chemical digestion (saliva containing

amylase starts carbohydrate breakdown).

● Esophagus: Peristalsis moves food to the stomach.

● Stomach: Mechanical digestion (churning), chemical digestion (pepsin breaks down

proteins), acidic environment (HCl).

● Small Intestine (3 parts):

○ Duodenum: Chemical digestion (enzymes from pancreas, bile from liver).

○ Jejunum & Ileum: Nutrient absorption via villi and microvilli.

● Large Intestine: Absorbs water, salts, and some vitamins; forms feces.

● Rectum and Anus: Elimination of undigested material.

8. Why have the respiratory system?

The respiratory system provides oxygen to the body and removes carbon dioxide. Oxygen is

essential for cellular respiration (ATP production), while carbon dioxide is a waste product that

needs to be exhaled.

9. What are the phases of gas exchange?1. 2. 3. Breathing: Inhalation and exhalation of air.

Transport of gases by the circulatory system: Oxygen is transported via red blood

cells; CO₂ is transported in plasma.

Cellular exchange: Oxygen is delivered to cells for cellular respiration, and CO₂ is

picked up for elimination.

10. Be able to list the characteristics of a respiratory surface and know the

respiratory surface in a human.

● Characteristics of a respiratory surface:

○ Moist (for gases to dissolve and diffuse).

○ Thin (to allow efficient gas diffusion).

○ Large surface area (to increase the exchange of gases).

○ Permeable to gases (O₂ and CO₂).

● Human respiratory surface: Alveoli (small air sacs in the lungs).

11. Be able to list the route through the human respiratory system and

explain what happens in each section, including key characteristics.

1. 2. 3. 4. 5. 6. 7. 8. Nostrils (Nares): Air enters; nose hairs filter large particles.

Nasal cavity: Warms and moistens air.

Pharynx: Passage for air and food.

Larynx (Voice box): Produces sound, protects the trachea.

Trachea (Windpipe): Passage for air to the lungs; lined with cilia to trap dust and

microbes.

Bronchi: Branches from the trachea to each lung.

Bronchioles: Smaller branches leading to alveoli.

Alveoli: Site of gas exchange (O₂ enters the blood, CO₂ leaves).

12. Differentiate between the two major types of breathing and give an

example for each.

● Positive Pressure Breathing: Air is forced into the lungs (e.g., amphibians like frogs).

● Negative Pressure Breathing: Air is drawn into the lungs due to a pressure difference

(e.g., humans and mammals).13. Describe the mechanism of inhalation.

● The diaphragm contracts and moves downward, increasing lung volume.

● The intercostal muscles contract, raising the ribcage.

● This creates a negative pressure inside the lungs, drawing air in.

14. Describe the mechanism of exhalation.

● The diaphragm relaxes and moves upward, decreasing lung volume.

● The intercostal muscles relax, lowering the ribcage.

● This increases the pressure inside the lungs, pushing air out.

15. How is breathing controlled in a human?

Breathing is controlled by the medulla oblongata and the pons in the brainstem.

● Medulla detects CO₂ levels in the blood and adjusts breathing rate accordingly.

● Pons helps regulate the smooth rhythm of breathing.

16. Know examples of problems with regular breathing.

● Asthma: Airway constriction and inflammation, leading to difficulty breathing.

● COPD (Chronic Obstructive Pulmonary Disease): Long-term blockage of airflow,

often due to smoking.

● Sleep Apnea: Interruption of breathing during sleep.

● Pneumonia: Infection of the lungs leading to difficulty breathing.

17. What are the basic functions of a circulatory system?

1. 2. 4. 5. Transport of gases (O₂ to cells, CO₂ to lungs).

Nutrient distribution (glucose, amino acids, etc.).

3. Waste removal (e.g., urea).

Immune function (transporting white blood cells).

Regulation of temperature and pH balance.18. Distinguish between no circulatory system, an open circulatory system,

and a closed circulatory system.

● No Circulatory System: Diffusion is used to transport gases and nutrients (e.g.,

sponges).

● Open Circulatory System: Blood is pumped into open spaces where it bathes organs

(e.g., arthropods).

● Closed Circulatory System: Blood is confined to vessels, providing more efficient

transport (e.g., humans).

19. What are the different types of blood vessels and their characteristics?

● Arteries: Carry oxygen-rich blood away from the heart; thick, elastic walls.

● Veins: Carry deoxygenated blood back to the heart; thinner walls, contain valves.

● Capillaries: Tiny vessels where exchange of gases, nutrients, and waste occurs; very

thin walls.

20. Vertebrates may have either a single circuit or double circuit circulatory

system. What is the difference?

● Single Circulatory System: Blood flows through the heart once (e.g., fish). Blood

passes through the heart only once per complete circuit.

● Double Circulatory System: Blood passes through the heart twice (e.g., humans). One

circuit to the lungs (pulmonary) and another to the body (systemic).

21. Be able to draw and label the general human circulation pattern.

● Pulmonary Circuit: Heart →