Cell Biology and Microscopy Concepts

Questions and Answers

What percentage of the cytosol is composed of organic compounds?

50%

18%

30% (correct)

65%

Which of the following compounds is classified as inorganic?

Water (correct)

Proteins

Vitamins

Nucleic acids

What function of the cell is primarily associated with the process of mitosis?

Produce energy

Facilitate transport

Provide structure and support

Facilitate growth (correct)

Which transport mechanism requires energy?

Active transport Signup and view all the answers

What is the primary site within cells for energy production?

Mitochondria Signup and view all the answers

What type of reaction includes the breakdown of complex molecules to release energy?

Catabolic reactions Signup and view all the answers

What characteristic do all true cells share?

A set of genes for regulating cellular activities Signup and view all the answers

Which of the following statements correctly describes prokaryotic cells?

They have no true nucleus and are considered more primitive. Signup and view all the answers

What term did Schwann introduce to describe the activities of cells?

Metabolism Signup and view all the answers

Which of the following is an exception to the cell theory?

Viruses Signup and view all the answers

Which of the following was NOT one of the basic characteristics of true cells?

Existence as unicellular organisms only Signup and view all the answers

What did Schleiden contribute to the evolution of cell theory?

Described the nucleoli and cellular duality Signup and view all the answers

Which statement about viruses is correct?

They use the metabolic machinery of host cells. Signup and view all the answers

Which of the following characteristics is NOT typical of prokaryotic cells?

Possession of multiple nuclei Signup and view all the answers

What is the structure of the bacterial chromosome?

Single, circular and double stranded DNA Signup and view all the answers

Where is the bacterial DNA located within the cell?

In the cytoplasm within a defined structure called nucleoid Signup and view all the answers

What type of proteins are found associated with prokaryotic DNA?

Small heat stable (HU) proteins Signup and view all the answers

What distinguishes bacterial ribosomes from eukaryotic ribosomes?

Bacterial ribosomes are 70s in size Signup and view all the answers

What role do 'R' factor plasmids play in bacterial cells?

They confer resistance to one or more drugs or antibiotics Signup and view all the answers

What is a key feature of mRNA synthesis in bacteria?

mRNA is directly available for translation without splicing Signup and view all the answers

How do plasmids contribute to bacterial evolution?

They can recombine with the main chromosome and introduce genetic variation Signup and view all the answers

What specific function do colicin-producing plasmids serve in bacteria?

They produce antibiotics that can kill competing bacteria Signup and view all the answers

What is a fundamental characteristic of eukaryotic cells?

They have a well-developed nucleus. Signup and view all the answers

Which component primarily separates the contents of the nucleus from the cytoplasm in eukaryotic cells?

Secondary membrane Signup and view all the answers

What term describes the fluid portion of the cytoplasm that exists outside the organelles?

Cytosol Signup and view all the answers

Which of the following is NOT considered a basic molecule of the cell?

Oxidants Signup and view all the answers

What primarily characterizes protoplasm?

It is alive due to the organization of non-living substances. Signup and view all the answers

In which type of organisms are eukaryotic cells typically found?

Algae and higher plants Signup and view all the answers

What is the primary role of nucleic acids in cells?

Information storage and transfer Signup and view all the answers

Which of the following statements about cytoplasm is correct?

Cytoplasm contains organelles and cytosol. Signup and view all the answers

Which of the following statements accurately describes the physical nature of cytosol?

It is colorless or greyish and translucent. Signup and view all the answers

How many of the naturally occurring elements are typically found in cytosol?

46 Signup and view all the answers

Which of the following elements constitutes the highest percentage in cytosol?

Oxygen Signup and view all the answers

Which of the following ions has a high concentration inside the cell?

K+ Signup and view all the answers

What role do trace elements play in cytosol?

They serve as cofactors important for metabolism. Signup and view all the answers

Which buffering system is associated with cytosol?

HPO4- Signup and view all the answers

Which essential element found in cytosol constitutes 1.14%?

Phosphorous Signup and view all the answers

What is the function of ions like K+ and Mg++ in cytosol?

They maintain osmotic pressure and acid-base balance. Signup and view all the answers

Study Notes

Cellular Structure and Theory

Various microorganisms observed include bacteria (bacilli, cocci, spirilla), protozoa, and Hydra.
Blood cells exhibit movement; significant for understanding circulatory functions.
Schleiden identified nucleoli, emphasizing each cell's dual existence: independent development and as part of multicellular organisms.
Schwann expanded cell theory showing living organisms consist of cells and their secretions and introduced the concept of metabolism.

Characteristics of True Cells

True cells are characterized by:
- A set of genes acting as blueprints for cellular regulation and reproduction.
- A limiting plasma membrane that manages the exchange of matter and energy.
- Metabolic machinery essential for sustaining life, including growth and repair.

Exceptions to Cell Theory

Viruses are exceptions as they lack protoplasm and utilize host cellular machinery for replication.
Primitive organisms exist that do not meet the full criteria of cellular organization.

Cell Types

The terms prokaryotic and eukaryotic cells were introduced by Hans Ris in the 1960s.

Prokaryotic Cells

Considered primitive cells, characterized by:
- Small size and single envelope system.
- Existence dates back approximately 3.5 billion years.
- Contain a nucleoid with circular, double-stranded DNA, not enclosed in a nuclear membrane.
- Absence of ribosomes in the nucleoid and no nucleolus present.

Cellular Structures in Prokaryotes

DNA is attached to the plasma membrane and carries membrane components upon isolation.
Contains rRNA and proteins forming ribosomes, sized at 70s, involved in protein synthesis.
Presence of plasmids, small circular DNA molecules, which can confer antibiotic resistance and assist in bacterial conjugation.

Eukaryotic Cells

Eukaryotic cells have a well-developed, defined nucleus.
Typically larger than prokaryotic cells with complex internal structures.
Featuring a secondary membrane around the nucleus and other organelles like endoplasmic reticulum.

Protoplasm and Cytosol

Protoplasm consists of living components made up of non-living substances interacting to support life.
Cytosol, the fluid portion of cytoplasm, is colorless, viscous, and contains around 46 naturally occurring elements essential for life.

Composition of Cytosol

Contains a mix of organic (30%) and inorganic (70%) compounds, with water making up about 65%.
Key elements: Carbon (20%), Oxygen (62%), Hydrogen (10%), among others, play vital roles in cellular function.

Functions of Cells

Provide structural framework and support to organisms.
Facilitate growth via mitosis, allowing tissue and organ development.
Enable active (energy-dependent) and passive (gradient-driven) transport of nutrients.
Produce energy through respiration, largely facilitated by mitochondria.
Conduct biochemical reactions, encompassing both anabolic and catabolic processes.
Aid in reproduction through mitosis (asexual) and meiosis (sexual).

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Description

This quiz explores key concepts in cell biology, focusing on the structure and function of various microorganisms such as bacteria and protozoa. Additionally, it delves into the contributions of scientists like Schleiden to the cell theory, emphasizing the dual life of cells and their role in multicellular organisms.