General Biology: Cytology

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Questions and Answers

What is the main reason for the unique shape of nerve cells?

To provide space for the hemoglobin

To store fat droplets

To accelerate the electric nerve impulse

To facilitate easy contact with other nerve cells (correct)

What is the main function of the plasma membrane?

To store genetic information

To synthesize proteins

To regulate what enters and leaves the cell (correct)

To generate energy for the cell

What is the main component of the plasma membrane?

Proteins

Carbohydrates

Phospholipids (correct)

Nucleic acids

What is the characteristic of the phosphate head of phospholipids?

Polar and hydrophilic Signup and view all the answers

What happens to the nucleus of human RBCs during development?

It is lost Signup and view all the answers

What is the main reason for the reduced cytoplasm in adipose cells?

To store fat droplets Signup and view all the answers

What is the branch of biology that deals with the study of form and structure of cells?

Cytology Signup and view all the answers

Who are the scientists credited with proposing the Cell Theory in 1839?

Schleiden and Schwann Signup and view all the answers

What is the basic unit of life according to the Cell Theory?

Cell Signup and view all the answers

What is the approximate number of cells in a typical human body?

A trillion Signup and view all the answers

What is passed on from cell to cell according to the modern version of the Cell Theory?

Heredity information (DNA) Signup and view all the answers

What is the term used to describe organisms consisting of only one cell?

Unicellular Signup and view all the answers

What is the function of nuclear pores?

To regulate the passage of RNA and other materials into and out of the nucleus Signup and view all the answers

What is the site where DNA is concentrated when it is in the process of making ribosomal RNA?

Nucleolus Signup and view all the answers

What is the function of mitochondria?

To transfer energy from organic molecules to ATP Signup and view all the answers

What is the structure that separates the mitochondrion from the cytosol?

Outer membrane Signup and view all the answers

What is the function of ribosomes?

To direct protein synthesis in the cytoplasm Signup and view all the answers

What is the number of mitochondria typically found in highly active cells?

Hundreds Signup and view all the answers

What is unique about the way the phospholipid bilayer behaves in the fluid mosaic model?

It behaves like a fluid Signup and view all the answers

What is the primary function of the nucleus in a eukaryotic cell?

To store genetic information Signup and view all the answers

What is the term for the threadlike material that makes up the DNA in a non-dividing cell?

Chromatin Signup and view all the answers

What is the process by which DNA is transcribed into RNA in the nucleus?

Transcription Signup and view all the answers

What is the term for the jellylike liquid that fills the nucleus and holds its contents?

Nucleoplasm Signup and view all the answers

What is the role of integral proteins in the cell membrane?

To transport molecules across the membrane Signup and view all the answers

What type of molecules do peroxisomes break down to produce energy for the mitochondria?

Fatty acid molecules Signup and view all the answers

What is the name of the structure from which microtubules radiate outward?

Centrosome Signup and view all the answers

What is the function of microtubules in the cell?

To hold organelles in place and maintain cell shape Signup and view all the answers

What is the function of peroxisomes in the liver and kidney cells?

To detoxify alcohol and other drugs Signup and view all the answers

What is the structure of microfilaments?

Long threads of actin Signup and view all the answers

What is the function of the cytoskeleton in the cell?

To give shape to the cell and act as internal tracks Signup and view all the answers

Study Notes

Cell Structure and Function

Nerve cells have a unique shape due to the necessity for long-distance signal transmission, which facilitates communication between different body parts.
The plasma membrane primarily functions to regulate the movement of substances in and out of the cell, maintaining homeostasis.
Phospholipids are the main component of the plasma membrane, providing structural integrity and fluidity.
The phosphate head of phospholipids is hydrophilic (water-attracting), allowing it to interact with water-based environments.

Development and Cellular Biology

During development, human red blood cells (RBCs) expel their nucleus, which contributes to their biconcave shape and maximizes hemoglobin capacity for oxygen transport.
Adipose cells exhibit reduced cytoplasm due to their primary role in fat storage, where lipids occupy most of the cell volume.
Cytology is the branch of biology focused on studying the form and structure of cells.

Cell Theory and Cellular Composition

The Cell Theory, proposed by scientists Schleiden, Schwann, and Virchow in 1839, establishes that all living things are composed of cells, and cells are the basic unit of life.
A typical human body contains approximately 37.2 trillion cells.
According to the modern version of the Cell Theory, genetic material (DNA) is passed on from cell to cell during division.

Cellular Organelles and Functions

Organisms made up of a single cell are termed unicellular organisms.
Nuclear pores serve to allow selective exchange of substances, including RNA and proteins, between the nucleus and cytoplasm.
The nucleolus is the site within the nucleus where DNA is concentrated during ribosomal RNA synthesis.
Mitochondria function as the powerhouse of the cell, generating energy in the form of ATP through cellular respiration.
The outer membrane of the mitochondria separates it from the cytosol, providing compartmentalization for metabolic processes.
Ribosomes are responsible for protein synthesis, translating mRNA into polypeptides.

Cellular Structures and Mechanisms

Highly active cells can contain hundreds to thousands of mitochondria to meet their energy demands.
In the fluid mosaic model, the phospholipid bilayer behaves like a dynamic 'sea' in which proteins float, allowing for flexibility and mobility.
The nucleus is the primary control center of a eukaryotic cell, housing the cell’s genetic material and regulating gene expression.
Chromatin is the term for the threadlike material comprising DNA in non-dividing cells, providing necessary packaging and protection.
Transcription is the process by which DNA is copied into RNA within the nucleus.

Cytoplasmic Component Functions

The nucleoplasm is the jelly-like substance that fills the nucleus, supporting its contents and facilitating molecular interactions.
Integral proteins embedded in the cell membrane play critical roles in transporting molecules and cell signaling.
Peroxisomes break down fatty acids and amino acids to produce energy necessary for mitochondrial functions.
Microtubules radiate outward from the centrosome, serving as structural components and facilitating intracellular transport and cell division.
Microtubules provide structural support, enabling cells to maintain their shape and participate in the movement of organelles.
In liver and kidney cells, peroxisomes detoxify harmful substances and are involved in lipid metabolism.
Microfilaments, composed of actin, contribute to cell shape, motility, and muscle contraction.
The cytoskeleton provides structural support, facilitates intracellular transport, and plays a role in cell division and signaling.

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Description

This quiz covers the basics of cytology, including the study of cell structure and form, cell theory, and the biological aspects of living cells.