Cell Biology Quiz: Organelles and Functions

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Questions and Answers

What form does DNA take in non-dividing cells?

Ribosomes

Endoplasmic reticulum

Chromatin (correct)

Chromosomes

Which function is NOT associated with the Smooth Endoplasmic Reticulum?

Transporting fat

Manufacturing proteins (correct)

Detoxifying drugs and pesticides

Breaking down glycogen to form glucose

What is the primary energy compound produced by the mitochondria?

Glycogen

ATP (correct)

RNA

Proteins

What is the primary role of lysosomes?

Digesting food particles Signup and view all the answers

Which organelle is primarily responsible for packaging and transporting materials out of the cell?

Golgi Apparatus Signup and view all the answers

What type of structures do microfilaments and microtubules form within the cell?

Cytoskeleton Signup and view all the answers

Which of the following statements about ribosomes is true?

They contain two sub-units. Signup and view all the answers

In dividing cells, what form does DNA take?

Chromosomes Signup and view all the answers

What is the primary function of the Na+ - K+ pump?

Create an electrochemical gradient Signup and view all the answers

Which of the following correctly defines exocytosis?

Expelling contents outside the cell Signup and view all the answers

What mechanism is described as 'cell drinking'?

Pinocytosis Signup and view all the answers

During filtration, what factors influence the amount of fluid filtered per time unit?

Hydrostatic pressure and membrane permeability Signup and view all the answers

What is the primary distinction between ionizing and non-ionizable solutes in osmosis?

Non-ionizable solutes produce more osmotic pressure. Signup and view all the answers

Which of the following best describes the function of osmosis?

Passive movement of water through a semipermeable membrane Signup and view all the answers

What is osmotic pressure?

The pressure required to prevent water movement in osmosis Signup and view all the answers

What sequence of contractions occurs during the cardiac cycle?

Contraction of the atria followed by ventricular contraction Signup and view all the answers

In which process do large particles enter the cell through membrane folding?

Endocytosis Signup and view all the answers

What causes depolarization in cardiac muscle cells?

Na+ influx Signup and view all the answers

How is the electrical activity of the heart recorded?

With electrodes placed on the body that detect potential fluctuations Signup and view all the answers

What does Einthoven's triangle represent in electrocardiography?

An equilateral triangle with electrical potentials at each vertex Signup and view all the answers

What is the function of the indifferent electrode in unipolar recording?

To serve as a reference point at zero potential Signup and view all the answers

Which of the following leads records the potential difference between the left leg and the right arm?

Lead II Signup and view all the answers

What occurs during diastole in the heart cycle?

All four chambers are relaxed Signup and view all the answers

Which unipolar lead configuration uses the right arm as the exploring electrode?

aVR Signup and view all the answers

What role does the receptor play in the feedback loop?

Detects changes in the body Signup and view all the answers

Which statement accurately describes negative feedback loops?

They counteract deviations from a normal range. Signup and view all the answers

An example of a positive feedback loop is:

Blood clotting process Signup and view all the answers

What happens if homeostasis fails to compensate for a disturbance?

Pathology may occur, potentially leading to illness or death. Signup and view all the answers

Which component of the feedback loop is responsible for sending output when changes are needed?

Control center Signup and view all the answers

Most feedback loops in the body are classified as which type?

Negative feedback loops Signup and view all the answers

Which of the following is NOT a component of the feedback loop?

Input stimulus Signup and view all the answers

Which process is an example of negative feedback?

Regulation of blood pressure Signup and view all the answers

What is the primary role of the plasma membrane?

To act as a barrier separating the cell from its environment Signup and view all the answers

Which part of the phospholipid molecule is hydrophilic?

The phosphate portion Signup and view all the answers

What describes the state of homeostasis in the human body?

Stability in internal environment despite external changes Signup and view all the answers

Which components make up the structure of the plasma membrane?

Phospholipids and cholesterol Signup and view all the answers

In the fluid mosaic model of the plasma membrane, what does the term 'mosaic' refer to?

The variety of proteins embedded within the membrane Signup and view all the answers

How do the hydrophilic and hydrophobic ends of phospholipids behave in the plasma membrane?

Hydrophilic ends face the extracellular and intracellular fluids, while hydrophobic ends meet in the interior Signup and view all the answers

What defines the structural and functional unit of life?

The cell Signup and view all the answers

Which is NOT a characteristic described about cells?

Cells utilize organ systems for function Signup and view all the answers

What is the primary role of the sinoatrial node (SAN) in the heart?

It generates the electrical impulse responsible for cardiac contraction. Signup and view all the answers

Which of the following best defines stroke volume (SV)?

The volume of blood pumped by each ventricle per beat. Signup and view all the answers

What does preload refer to in cardiac physiology?

The volume of blood in the ventricles before contraction. Signup and view all the answers

How is cardiac output (CO) calculated?

By multiplying heart rate (HR) by stroke volume (SV). Signup and view all the answers

What does the ejection fraction indicate?

The ratio of stroke volume to end diastolic volume. Signup and view all the answers

Which property allows cardiac muscle to initiate its beats independently of the nervous system?

Rhythmicity Signup and view all the answers

What does the cardiac index relate to?

Cardiac output adjusted for body surface area. Signup and view all the answers

During which phase of the cardiac cycle does afterload act on the ventricles?

During contraction (systole) Signup and view all the answers

Study Notes

General Characteristics of the Cardiovascular System

The cardiovascular system is comprised of the heart and blood vessels
The heart acts as a pressure pump
The left ventricle pumps blood at high pressure to the systemic circulation
The right ventricle pumps blood at lower pressure to the pulmonary circulation
Semilunar valves regulate blood flow between the ventricles and blood vessels

Heart Chambers and Valves

The heart has four chambers: two atria and two ventricles
Atrioventricular (AV) valves (tricuspid and mitral) facilitate one-way blood flow from atria to ventricles
Semilunar valves (aortic and pulmonary) regulate blood flow from ventricles to arteries

Organization of the Circulatory Systems

Systemic circulation: carries oxygenated blood from the left ventricle around the body, where it releases oxygen and absorbs carbon dioxide, then returns to the right atrium
Pulmonary circulation: carries deoxygenated blood from the right ventricle to the lungs, where it absorbs oxygen and releases carbon dioxide, before returning to the left heart

Blood Vessels

Arteries carry blood away from the heart
Veins carry blood toward the heart
Capillaries facilitate the exchange of substances across the vessel wall

Blood Vessel Types and Functions

Arteries: transport high-pressure blood from the heart.
Arterioles: act as reservoirs of blood and transport low-pressure blood.
Capillaries: facilitate gas exchange, nutrient transfer, and waste removal
Venules: connect capillaries to veins.
Veins: transport low-pressure blood toward the heart

Cardiac Cycle

A repeating sequence of contraction and relaxation of the atria and ventricles.
The sequence includes four phases: atrial systole, isovolumetric contraction, ejection, and isovolumetric relaxation
Pressure changes in the heart chambers correlate with the opening and closing of heart valves

Cardiac Cycle Events

Atrial systole: contraction of the atria causes a rise in atrial pressure, forcing blood into the ventricles
Isovolumetric contraction: ventricular contraction increases pressure but volume remains the same until the pressure exceeds pressure of the pulmonary/aortic outflow valves.
Ejection: when ventricular pressure exceeds pressure in the arteries, the outflow valves open, and blood is pumped out
Isometric relaxation: ventricular relaxation leads to a decrease in ventricular pressure, closing the outflow valves, and then the heart is relaxed

Important Terms Relating to the Cardiac Cycle

Preload: the load acting on the ventricle before contraction (determined by venous return or end-diastolic volume)
Afterload: the load acting on the ventricle during contraction (determined by arterial resistance or total peripheral resistance)

Electrocardiography (ECG)

A recording of the heart's electrical activity
ECG recording represents the sum of electrical activity across the heart
Electrodes placed on the body's surface detect these electrical changes
ECG findings can help diagnose various cardiac abnormalities and conditions

Heart Rate Determination from ECG

A normal ECG reading has a P wave, a PR interval, the QRS complex, and a T wave.
The rate is determined by calculating the time between consecutive R peaks (RR interval)

Applications of ECG

Arrhythmias: abnormal heart rhythms
Disorders in the activation sequence: problems in conduction of electrical signals
Myocardial ischemia and infarction: decreased blood flow to the heart muscle
Electrolyte imbalance: irregular levels of certain electrolytes (e.g., potassium and calcium)
Carditis (Pericarditis/Myocarditis)
Pacemaker monitoring

Blood

Fluid connective tissue
Contains cells (RBCs, WBCs, platelets) suspended in a fluid matrix called plasma
Cellular component includes red blood cells (erythrocytes), white blood cells (leukocytes) and platelets (thrombocytes).
The liquid component includes water (90%), plasma proteins, lipids, hormones, enzymes, nutrients and waste products

Blood Classifications

Blood grouped into O-A-B blood types, based on the presence or absence of A and B antigens (agglutinogens) on red blood cells.
Rh factor; either the presence or absence of the Rh antigen (D antigen) on the red blood cells.

Erythropoiesis

Process of formation of red blood cells (erythrocytes)
Occurs in the bone marrow of adults (axial skeleton)

Erythropoiesis factors

Essential factors for proper erythrocyte formation such as:
Diet.
Hormones.
Iron.
Cobalt

Anemia

A condition caused by either a low RBC count or a low hemoglobin content, which decreases the blood's oxygen-carrying capacity;
Etiological classification: hemorrhagic anemia (blood loss), decreased production of RBCs and hemolytic anemia (RBC destruction)
Morphological classification: normocytic normochromic, microcytic hypochromic or macrocytic normochromic

WBC

Leukocytes: mobile defense units formed both in the bone marrow and lymph tissue.
Involved in immune response
Variations in WBC count; Leukopenia (decreased count) or Leukocytosis (increased count)
Leukocytes can be: neutrophils, lymphocytes, monocytes, eosinophils (allergic), and basophils (histamine)
Leukemia; a cancer affecting bone marrow white blood cells.

Platelets (Thrombocytes)

Function: clotting
Platelet formation: megakaryocytes fragment in the bone marrow to form platelets when activated
Platelet count variations; Thrombocytopenia
Platelets in clotting: activation causes the formation of a platelet plug (temporary) and the definitive plug (coagulation)

Cardiovascular System (CVS)

The circulatory system, composed of blood, the heart, and blood vessels, to transport blood and maintain homeostasis.
Blood delivers essential nutrients, gases, and removes metabolic wastes.
The heart pumps blood, and blood vessels transport it throughout the body.
Important circulatory system components include arteries, veins, and capillaries.

Hemolytic Disease of the Newborn

A condition that occurs when a mother is Rh-negative and a father is Rh-positive.
Mother's antibodies attack fetus's Rh positive blood cells causing complications
Prevention is possible by administering anti-D immunoglobulin

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Description

Test your knowledge on key concepts within cell biology, including the structure and function of organelles such as mitochondria, lysosomes, and the Smooth Endoplasmic Reticulum. This quiz covers important topics like DNA structure in dividing and non-dividing cells, osmosis, and the cardiac cycle. Perfect for students studying cell biology at any level.