The Human Cell Quiz

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Questions and Answers

What are the functional subunits of chromosomes called?

Exons

Chromatids

Genes (correct)

Nucleotides

What primary role does the nucleolus play in the cell?

Synthesize and assemble rRNA into ribosomal subunits (correct)

Facilitate protein digestion

Store genetic material

Regulate cellular metabolism

Which process is associated with the formation of two identical daughter cells?

Translation

Meiosis

Transcription

Mitosis (correct)

Which component of the cell is continuous with the endoplasmic reticulum?

Nuclear membrane Signup and view all the answers

What happens to RNA synthesized in the nucleus?

It is transported to the cytoplasm through nuclear pores Signup and view all the answers

What is the primary function of the nucleus in eukaryotic cells?

To store genetic information Signup and view all the answers

Which of the following best describes the plasma membrane?

A double layer of phospholipids with embedded proteins Signup and view all the answers

Which element makes up the largest percentage of the human body mass?

Oxygen Signup and view all the answers

What do secretory vesicles primarily store?

Protein proenzymes Signup and view all the answers

What type of transport is exemplified by the sodium glucose transporter?

Symport Signup and view all the answers

What distinguishes eukaryotic cells from prokaryotic cells?

Eukaryotic cells contain membrane-bound organelles Signup and view all the answers

What distinguishes rough endoplasmic reticulum from smooth endoplasmic reticulum?

Presence of ribosomes Signup and view all the answers

How are prokaryotic ribosomes different from eukaryotic ribosomes?

Prokaryotic ribosomes have a size of 70S compared to 80S in eukaryotes Signup and view all the answers

What is the primary function of the Golgi apparatus?

Store and distribute proteins and lipids Signup and view all the answers

Which of the following components is most abundant in the cytoplasm of a cell?

Water Signup and view all the answers

What is the main function of organelles within the cell?

They perform specific tasks to keep the cell functioning Signup and view all the answers

What happens during the electron transport chain?

Electrons are transferred to oxygen through protein complexes. Signup and view all the answers

Which component is not included in the definition of cytoplasm?

Nucleus Signup and view all the answers

What role do microtubules play in a cell?

Support intracellular transport Signup and view all the answers

How do peroxisomes differ from lysosomes?

Mechanism of formation Signup and view all the answers

Which type of ribosome is found in eukaryotic cells?

80S Signup and view all the answers

Which cell structure primarily controls the movement of substances in and out of a cell?

Plasma membrane Signup and view all the answers

What type of cells prominently feature a Golgi apparatus?

Secretory cells Signup and view all the answers

What type of enzyme do lysosomes contain for digestion?

Hydrolase Signup and view all the answers

Where does glycolysis occur in the cell?

Cytoplasm Signup and view all the answers

Which statement is true regarding mitochondria?

They are involved in energy production through chemical processes. Signup and view all the answers

What is the primary function of mitochondria within a cell?

Cellular respiration and ATP production Signup and view all the answers

What is the main structural role of intermediate filaments?

Providing structural support and maintaining cell shape Signup and view all the answers

Which type of transport requires energy to move substances against their concentration gradient?

Primary active transport Signup and view all the answers

What is the primary function of aquaporins in cell membranes?

Transporting water across membranes Signup and view all the answers

Which of the following statements about passive transport is correct?

It includes processes like osmosis and facilitated diffusion. Signup and view all the answers

What is the role of cholesterol in the cell membrane?

Modulating membrane fluidity and stability Signup and view all the answers

Which is true regarding the nucleus of a cell?

It acts as the control center for cellular activities. Signup and view all the answers

What is the primary purpose of cell adhesion molecules like cadherins?

Facilitating communication between cells Signup and view all the answers

Which organelle is responsible for ATP production in cells?

Mitochondria Signup and view all the answers

Which of the following proteins are involved in cell signaling as G-protein coupled receptors?

Adrenaline receptors Signup and view all the answers

What is the primary function of cytokines like TNF-alpha and IL-6?

Activating immune responses Signup and view all the answers

Study Notes

Overview of the Cell

Cell is the smallest structural and functional unit of life, serving as the building block of all living organisms.
Eukaryotic cells possess a nucleus with a nuclear membrane, while prokaryotic cells have DNA located in a nucleoid region.
Eukaryotic cells are typically larger (10-100 micrometers) compared to prokaryotic cells (0.1 to 5.0 micrometers).
Prokaryotes lack membrane-bound organelles and exhibit a less complex cytoskeleton.

Cellular Composition

Main cellular components: cell membrane, nucleus, cytoplasm, and various organelles.
Key cellular contents include water, proteins, lipids, carbohydrates, nucleic acids, electrolytes, vitamins, and trace minerals.
Oxygen constitutes 65% of body mass; carbon accounts for 18%, hydrogen for 10%, and nitrogen for 3%.

Electrolyte Importance

Important electrolytes include sodium (0.1%), potassium (0.2%), calcium, magnesium, and several trace minerals essential for various physiological processes.

Cell Size Variability

Animal cells typically range between 10 to 30 micrometers.
The smallest cells are about 6-8 micrometers, while the largest, like oocytes, can reach 100 micrometers.
Neurons can extend over a meter, and muscle cells may be as long as 30 cm.

Plasma Membrane Structure

Composed of a phospholipid bilayer with embedded proteins, providing selective permeability and structural support.
Hydrophilic phosphate heads face intracellular and extracellular fluids, while hydrophobic fatty acid tails face each other.

Membrane Proteins Functions

Integral proteins facilitate transport (e.g., sodium-potassium pump), reception of signals, and enzymatic activities.
Peripheral proteins contribute to structural support and signaling.
Cholesterol modulates membrane fluidity.

Organelles and Their Functions

Organelles perform specialized tasks essential for cell survival and function: nucleolus, mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus, lysosomes, and cytoskeleton.
The nucleus acts as the control center, housing genetic material and regulating cellular activities.

Cellular Transportation Mechanisms

Passive transport does not require energy, including simple diffusion, facilitated diffusion, and osmosis.
Active transport requires energy, including primary active transport (e.g., sodium-potassium pump) and secondary active transport (co-transport mechanisms).

Cytoplasm and Cytosol

Cytoplasm consists of the jelly-like cytosol and organelles, excluding the nucleus.

Endoplasmic Reticulum Types

Rough ER, covered in ribosomes, synthesizes proteins for internal and external use.
Smooth ER, without ribosomes, synthesizes lipids and fatty substances.

Golgi Apparatus Functions

Stacked vesicles involved in packing, modifying, and distributing proteins and lipids from the endoplasmic reticulum.

Ribosomes

Comprised of rRNA and proteins; they synthesize proteins using the genetic instructions from DNA.
Eukaryotic ribosomes are 80S, while prokaryotic ribosomes are 70S.

Lysosomes and Peroxisomes

Lysosomes contain digestive enzymes to break down cellular waste and ingested material.
Peroxisomes contain oxidizing enzymes and are formed by self-replication.

Mitochondria

Known as the "powerhouse" of the cell, mitochondria facilitate ATP synthesis through cellular respiration.
They contain their own DNA and are self-replicating.

Cellular Respiration Process

Involves multiple steps to convert glucose and oxygen into ATP, carbon dioxide, and water:
- Glycolysis occurs in the cytoplasm, yielding 2 ATP and 2 NADH.
- Citric Acid Cycle (Krebs Cycle) takes place in the mitochondrial matrix and produces high-energy carriers NADH and FADH2.
- Electron Transport Chain in the inner mitochondrial membrane contributes to ATP synthesis through chemiosmosis.

Cytoskeleton Functionality

Composed of microfilaments, intermediate filaments, and microtubules, providing structural support and facilitating intracellular transport, cell division, and signaling.

Nucleus Specifics

Functions as the cell's control center, housing genetic material (DNA) and regulatory mechanisms for cell activities including gene expression and division.
Surrounded by a nuclear membrane with nuclear pores for transport of molecules like mRNA.

Nucleolus Role

Synthesizes and assembles rRNA into ribosomal subunits, enlarging during active protein synthesis phases.

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Description

Test your knowledge about the human cell with this quiz focusing on its structure, contents, and functions of organelles. Topics include cellular respiration and the comparison between eukaryotic and prokaryotic cells. Challenge yourself and learn more about the building blocks of life!