Biology - Eukaryotic Cell Structure

Questions and Answers

What was the significant contribution of Rudolf Virchow to cell biology?

He discovered the structure of the cell membrane.

He proposed that all living things are made of cells.

He identified the role of enzymes in cellular processes.

He stated that all cells arise from preexisting cells. (correct)

Which of the following best describes the molecular composition of the cell membrane?

It contains equal parts of proteins and lipids with some carbohydrates. (correct)

It is composed entirely of carbohydrates and lipids.

It is primarily made of nucleic acids and salts.

It consists mainly of proteins with a small amount of carbohydrates.

According to cell theory, what primarily determines the activity of an organism?

The types of nutrients consumed

The function of its organs

The collective activities of its cells (correct)

The sum of genetic information

Who was responsible for coining the term 'cell' and what significant observation did he make?

Robert Hooke; he observed cork and described its cellular structure. Signup and view all the answers

Which elements play a significant role in the composition of cells as mentioned in the content?

Carbon, hydrogen, oxygen, and nitrogen Signup and view all the answers

What is the primary composition of organic compounds in a cell?

Proteins – 10 – 20% Signup and view all the answers

Which of the following structures contains enzymes for hydrolysis?

Lysosomes Signup and view all the answers

Which statement correctly describes mitochondria?

They have a double membrane and contain RNA and DNA. Signup and view all the answers

What percentage of a cell's composition is comprised of water?

70 – 75% Signup and view all the answers

Which inorganic compounds are found in cells?

Na, K, Mg, Cu Signup and view all the answers

What is a characteristic of the phospholipid molecules listed?

They contain a hydrophobic tail and a hydrophilic head. Signup and view all the answers

Which function is not associated with the cellular structure mentioned?

Facilitates cell division. Signup and view all the answers

Which statement regarding peroxisomes is accurate?

They contain enzymes capable of degrading fatty acids. Signup and view all the answers

What structural characteristic is common among eukaryotic cells?

Shared common features, varying in size and shape. Signup and view all the answers

Which of the following phospholipids is primarily found in the neuronal membrane?

Sphingomyelin Signup and view all the answers

What is one of the primary functions of the cell's cytoskeleton?

Maintaining structural support Signup and view all the answers

Which of the following correctly describes prokaryotic cells?

Lack subcellular organelles Signup and view all the answers

What role do ion channels serve in eukaryotic cells?

Facilitate ion transport Signup and view all the answers

Which substance is involved in detoxifying harmful materials in the cell?

Functions associated with the Golgi apparatus Signup and view all the answers

What is the primary composition of DNA in prokaryotic cells?

Condensed within the cytosol as nucleoid Signup and view all the answers

What is a major difference between eukaryotic and prokaryotic cells?

Prokaryotic cells lack a membrane-bound nucleus Signup and view all the answers

Which function is NOT associated with vacuoles?

Protein synthesis Signup and view all the answers

What characteristic is true about mesosomes in prokaryotic cells?

They structure cells for better organization Signup and view all the answers

What is the primary function of the sodium-potassium pump?

To transport sodium out and potassium into the cell Signup and view all the answers

Which process is NOT part of passive transport?

Active transport Signup and view all the answers

During which phase of the cell life cycle does the cell primarily grow and synthesize components for replication?

G1 phase Signup and view all the answers

What is the main driving force for diffusion?

Concentration gradient Signup and view all the answers

Which of the following is an example of facilitated diffusion?

Movement of glucose through protein channels Signup and view all the answers

In which of the following processes is ATP not utilized?

Facilitated diffusion Signup and view all the answers

What role do microtubules and microfilaments play in cells?

They aid in transport and structural integrity Signup and view all the answers

What characterizes osmosis as a type of passive transport?

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

Study Notes

Enzymes, Nutrients, and Inorganic Salts

Key elements in organisms include enzymes, nutrients, and inorganic salts, primarily dissolved in aqueous solutions.
Homoeostasis is crucial for maintaining balance within biological systems.

Historical Notes on Cell

Robert Hooke is credited with the discovery of the cell.
Matthias Schleiden and Theodor Schwann established that all plant and animal tissues are made of cells.
Rudolf Virchow proposed the theory of biogenesis, stating that cells arise from pre-existing cells.

Cell Theory

The functioning of an organism is determined by the collective actions of its cells.
Principle of complementarity suggests that the structure of a cell relates directly to its function.

Molecular Composition of Cells

Water constitutes approximately 70-75% of the cell's composition.
Organic compounds make up about 25-30%:
- Proteins: 10-20%
- Nucleic acids: 7-10%
- Polysaccharides: 2-5%
- Lipids: 3%
Inorganic compounds present include Na, K, Mg, and Cu.
Proteins are the most abundant organic component within cells.

Eukaryotic Cell Structure and Function

Eukaryotic cells form tissues or organs and ultimately organisms, exhibiting diverse sizes and shapes, yet share common structural features.
Cell functions include modification, packaging, and sorting of materials from the endoplasmic reticulum.
Eukaryotic cells serve as semi-permeable barriers and are involved in detoxifying harmful substances and cholesterol biosynthesis.

Phospholipid Molecules

Important phospholipids include phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), and sphingomyelin.
Functions of phospholipids include maintaining fluidity, acting as a physical barrier, and facilitating cell communication.

Important Notes in Eukaryotic Cells

Ion channels facilitate transport of ions within the cytosol.
Vacuoles provide storage and transport functions.
Cell coat contributes to cell recognition and protection.

Important Notes in Prokaryotic Cells

Prokaryotes (Eubacteria and Archaebacteria) are widely abundant globally.
They lack a membrane-bound nucleus and subcellular organelles.
Surrounded by plasma membrane and condensed DNA forms nucleoid; some possess flagella.

Cytoskeleton

Organized network of protein filaments maintains structural support and cellular organization.
Composed of microfilaments, intermediate filaments, and microtubules.

Cell Membrane Transport

Passive transport includes diffusion from high to low concentration:
- Simple diffusion
- Facilitated diffusion
- Osmosis

Sodium-Potassium Pump

Critical enzyme mechanism, sodium–potassium activated ATPase, exchanges Na+ out for K+ in.
Cell life cycle includes cell division, essential for growth and development, consisting of four stages:
- G1 (gap 1): Active cell growth and preparation for replication.

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Description

This quiz covers essential concepts related to eukaryotic cell structure, including the role of enzymes, nutrients, and inorganic salts in cellular function. It also highlights historical contributions to cell theory by scientists like Robert Hooke and the cellular components outlined by Schleiden and Schwann.