Biology Chapter on Cell Structure

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Questions and Answers

What is the size range of cells mentioned?

1 to 5 µm

0.01 to 0.1 µm

0.5 to 1 µm

0.1 to 0.5 µm (correct)

Which of the following correctly characterizes eukaryotic cells?

They exhibit only cellular movement.

They reproduce only asexually.

They lack a true nucleus.

They can range from 10–100 µm in diameter. (correct)

Who first discovered the cell by observing a piece of cork?

Robert Hooke (correct)

Robert Brown

Anton Van Leeuwenhoek

Theodor Schwann

What term did Hooke use to describe the structures he observed?

Cells Signup and view all the answers

Which scientists are credited with proposing cell theory?

Theodor Schwann, Matthias Schleiden, Rudolf Virchow Signup and view all the answers

Which of the following statements is part of the cell theory?

All living species are composed of cells. Signup and view all the answers

What does a modern version of the cell theory include regarding energy?

Energy flows within the cells. Signup and view all the answers

What type of reproduction is eukaryotic cells capable of?

Both sexual and asexual reproduction Signup and view all the answers

What is the primary function of the cell wall in plant cells?

Provides support and structure Signup and view all the answers

Which of the following statements is true about plant cells?

They contain chloroplasts for photosynthesis. Signup and view all the answers

What role does the nucleus play in eukaryotic cells?

It stores genetic information. Signup and view all the answers

What is a key difference between plant cells and animal cells?

Plant cells have a cell wall; animal cells do not. Signup and view all the answers

What characterizes dermal tissue in plants?

It protects the plant and controls interactions with its environment. Signup and view all the answers

What is the primary function of meristem tissue in plants?

Form new cells through mitotic division Signup and view all the answers

What is the role of phloem cells in plant biology?

Transport food prepared by the leaves Signup and view all the answers

Which of the following components is found in plant cells but not in animal cells?

Chloroplasts Signup and view all the answers

The central vacuole in plant cells serves what primary function?

Storage of nutrients and waste products Signup and view all the answers

Which type of tissue is primarily responsible for water and mineral transport in plants?

Xylem cells Signup and view all the answers

What characteristic is shared by both plant and animal cells?

Both have membrane-bound organelles. Signup and view all the answers

Which of the following tissues is considered to be involved in the metabolism of the plant?

Ground tissue Signup and view all the answers

What is the primary function of plastids in plant cells?

Storing starch and facilitating photosynthesis Signup and view all the answers

What is the main function of hydathodes in plants?

Dispose of excess water Signup and view all the answers

How do plant cells primarily obtain energy?

Via photosynthesis in chloroplasts Signup and view all the answers

Which of the following structures is responsible for protein synthesis in the cell?

Ribosomes Signup and view all the answers

Which of the following best describes the epidermis in plants?

The outermost protective dermal layer Signup and view all the answers

What is the role of the Golgi Apparatus in a plant cell?

Distributing synthesized macromolecules Signup and view all the answers

What type of division occurs in meristem tissue?

Mitosis Signup and view all the answers

Which type of plastid is primarily involved in photosynthesis?

Chloroplasts Signup and view all the answers

What is a common characteristic of mitochondria?

Has a double membrane structure Signup and view all the answers

Which type of organelle is involved in the breakdown of carbohydrate molecules to provide energy?

Mitochondria Signup and view all the answers

Which components make up ribosomes?

RNA and protein Signup and view all the answers

What distinguishes plant cells from animal cells in terms of structure?

Presence of plastids Signup and view all the answers

What primary function do trichomes serve in plants?

Protection from predators and pathogens Signup and view all the answers

Which type of plant tissue provides mechanical support and can be characterized by thickened cell walls?

Sclerenchyma Signup and view all the answers

What is the primary role of stomatal guard cells in plants?

Regulating gas exchange and water retention Signup and view all the answers

What components make up the vascular tissue in plants?

Xylem and phloem Signup and view all the answers

Which type of ground tissue is primarily responsible for the storage of food and water in plants?

Parenchyma Signup and view all the answers

What is the primary function of xylem in plants?

Transportation of water and minerals Signup and view all the answers

How does collenchyma tissue contribute to a plant's structure?

Offers flexible mechanical support Signup and view all the answers

Which statement is true regarding phloem?

It transports products of photosynthesis. Signup and view all the answers

Study Notes

Cell Structure and Function

Cell sizes range from 0.1 to 0.5 µm in diameter, indicating varying shapes and sizes.
Cells are the basic unit of life, with all living organisms composed of them, differing in number between species.
Human cells outnumber bacterial cells significantly.
Cells can reproduce either asexually or sexually, depending on the type.

Historical Background

Robert Hooke discovered and named "cells" in the 17th century while observing cork under a microscope.
Anton Van Leeuwenhoek observed movement in cells and coined the term "animalcules" for microscopic life forms.
Robert Brown identified and described the nucleus in plant cells.

Cell Theory

Proposed by Theodor Schwann, Matthias Schleiden, and Rudolf Virchow:
- All living organisms are composed of cells.
- The cell is the fundamental unit of life.
- Cells arise from pre-existing cells.
Modern cell theory includes:
- Energy flows occur within cells.
- Genetic information is transferred from one cell to another.
- Chemical composition is consistent among cells.

Functions of Cells

Provide structural support.
Facilitate growth and reproduction.
Transport essential substances.
Produce energy for metabolism.

Plant Cell Structure

Cell Wall: Rigid structure made of cellulose, pectin, and hemicellulose, located outside the cell membrane.
Cell Membrane: Semi-permeable layer controlling the entry and exit of substances.

Key Organelles in Plant Cells

Nucleus: Contains DNA for cell division and metabolism.
Plastids: Store starch and conduct photosynthesis. Types include:
- Leucoplasts: Store starch in non-photosynthetic tissues.
- Chloroplasts: Involved in gas exchange and photosynthesis.
Golgi Apparatus: Distributes macromolecules within the cell.
Ribosomes: Sites of protein synthesis, made of RNA and protein.
Mitochondria: Generate energy by breaking down carbohydrates.

Vascular Tissue in Plants

Xylem: Transfers water and minerals from roots to leaves; consists of dead cells.
Phloem: Distributes food from leaves to other plant parts.

Plant Tissue Types

Meristematic Tissue: Found at growth regions; capable of cell division.
Dermal Tissue: Protective layer controlling water loss and interaction with the environment.
- Includes epidermis, stomata for gas exchange, and structures like trichomes and thorns for protection.
Ground Tissue: Provides support and storage; classified into:
- Parenchyma: Stores food and water.
- Collenchyma: Adds mechanical support.
- Sclerenchyma: Contains thick walls for durability.

Summary of Key Functions in Plant Cells

Major functions include photosynthesis, structural support, and nutrient transport, essential for growth and development of plants.

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Description

This quiz focuses on the basic structure and function of cells, including their varying shapes and sizes. It discusses the significance of cells as the fundamental unit of life and compares the number of cells in humans and bacteria. Additionally, it touches upon the reproduction methods of cells and the types of hereditary material.