History and Definition of Cells

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Questions and Answers

Who coined the term 'cell' in 1665?

Robert Brown

Robert Hooke (correct)

Theodor Schwann

Antonie van Leeuwenhoek

What significant discovery did Robert Brown make in 1831?

Cellular respiration

Cell division

The nucleus (correct)

Organelles in cells

What is the primary function of the cell membrane?

Supports and protects the cell

Produces energy for the cell

Contains genetic material

Controls movement in and out of the cell (correct)

Which of the following statements is true about cell theory?

All living things are made up of cells. Signup and view all the answers

Which organelle is responsible for producing energy in the cell?

Mitochondria Signup and view all the answers

Which of the following are characteristics of prokaryotic cells?

Do not have structures surrounded by membranes. Signup and view all the answers

What did Theodor Schwann contribute to cell biology?

Identified cells as the basic unit of animals. Signup and view all the answers

What is the role of ribosomes in a cell?

Make proteins Signup and view all the answers

Which type of cells are known to lack membrane-bound organelles?

Prokaryotic cells Signup and view all the answers

Which organelle is specifically found in plant cells but not in animal cells?

Chloroplasts Signup and view all the answers

What is one of the main functions of vacuoles in plant cells?

Store substances and maintain cell shape Signup and view all the answers

What is the smallest unit capable of performing life functions?

Cell Signup and view all the answers

Which scientist proposed that all cells arise from preexisting cells in 1858?

Virchow Signup and view all the answers

What structure surrounds the nucleus and allows material to enter and exit?

Nuclear membrane Signup and view all the answers

What is the primary role of lysosomes in the cell?

Digest materials and remove waste Signup and view all the answers

Which organelle is known as the 'packaging plant' of the cell?

Golgi Bodies Signup and view all the answers

Which of the following statements is true regarding chloroplasts?

They contain chlorophyll and are involved in photosynthesis. Signup and view all the answers

Which organelle is associated with the production of ribosomes?

Nucleolus Signup and view all the answers

What is the main function of carbohydrates in the human body?

Serve as the body's main source of energy Signup and view all the answers

Which of the following best describes monosaccharides?

The smallest unit of carbohydrates, also known as simple sugars Signup and view all the answers

What role do enzymes play in the breakdown of carbohydrates?

They act as catalysts that speed up the breakdown process Signup and view all the answers

Which carbohydrate category includes chains of 3-10 monosaccharides?

Oligosaccharides Signup and view all the answers

What distinguishes polysaccharides from other carbohydrates?

They consist of many glucose units, typically 300-1000 Signup and view all the answers

Which of the following statements about enzymes is true?

Enzymes are unchanged after speeding up reactions Signup and view all the answers

What is the smallest unit of carbohydrates called?

Monosaccharide Signup and view all the answers

Which type of carbohydrate is primarily involved in providing energy immediately?

Simple sugars Signup and view all the answers

What is the role of enzymes in biological processes?

Enzymes help speed up life processes. Signup and view all the answers

Which of the following best describes amino acids?

They are the building blocks of proteins. Signup and view all the answers

How are polypeptides formed?

By the bonding of amino acids in chains. Signup and view all the answers

What composes lipids such as triglycerides?

Glycerol and three fatty acids. Signup and view all the answers

What are nucleic acids primarily known for?

Storing and carrying genetic information. Signup and view all the answers

Which of the following factors does NOT affect enzyme activity?

Weight of the enzyme Signup and view all the answers

What happens to proteins in the stomach and small intestine?

They are broken down into amino acids. Signup and view all the answers

Which statement about nucleotides is true?

All nucleic acids are made from combinations of nucleotides. Signup and view all the answers

Study Notes

History of Cell Study

Robert Hooke (1665) coined the term "cell" while examining cork cells.
Antonie van Leeuwenhoek developed optics to visualize single cells; his technology was lost for nearly 200 years.
Robert Brown (1831) discovered the "nucleus" within cells.
Theodor Schwann (1838) viewed animal cells and concluded that cells are elementary particles in all life forms.
Mattias Schleiden proposed that cells are the fundamental basis of life.
Rudolf Virchow (1858) stated that all cells arise from preexisting cells.
Cell theory established three key principles:
- All living organisms are composed of one or more cells.
- Cells are the basic unit of structure and function.
- All cells originate from existing cells.

Definition of Cell

A cell is the smallest unit capable of performing life functions.
Examples include:
- Amoeba Proteus
- Plant Stem Cells
- Bacteria
- Red Blood Cells
- Nerve Cells

Types of Cells

Prokaryotic Cells:
- Lack membrane-bound structures.
- Few internal components.
- Examples include bacteria.
Eukaryotic Cells:
- Contain organelles surrounded by membranes.
- Comprise most living organisms, including plants and animals.

Common Cell Structures

Found in both Plant and Animal Cells:
- Nucleus
- Golgi Complex
- Mitochondrion
- Lysosomes
- Endoplasmic Reticulum
- Cell Membrane
- Ribosomes
- Vacuoles
Unique to Plant Cells:
- Chloroplasts
- Cell Wall

Cell Components

Cell Membrane:
- Outer membrane controlling the movement of substances in and out of the cell.
- Composed of a double lipid layer.
Cell Wall:
- Predominantly found in plant cells and bacteria.
- Provides structural support and protection.
Nucleus:
- Directs cell activities and contains genetic material (DNA).
- Surrounded by a nuclear membrane.
Nuclear Membrane:
- Composed of two layers with openings for material exchange.
Chromosomes:
- Located in the nucleus, made of DNA, containing genetic instructions.
Nucleolus:
- Found within the nucleus, involved in RNA production for protein synthesis.
Cytoplasm:
- Gel-like substance filled with hereditary material, lies between the nucleus and the cell membrane.
Endoplasmic Reticulum (ER):
- Network for transporting materials within the cell.
- Smooth ER lacks ribosomes, while Rough ER has ribosomes on its surface.
Ribosomes:
- Sites for protein synthesis, numerous in every cell.
Mitochondria:
- Powerhouses of the cell, generating energy through chemical reactions.
Golgi Bodies:
- Function in packaging proteins and transporting materials within and outside the cell.
Lysosomes:
- Digestive organelles, breaking down waste and recycling cellular components.
Vacuoles:
- Membrane-bound sacs for storage, digestion, and waste removal; help maintain plant cell shape.
Chloroplasts:
- Photosynthesis occurs here in plant cells, containing chlorophyll.

Macromolecules

Macromolecules are crucial for human body functions:
- Carbohydrates: Main energy source, consists of carbon, hydrogen, and oxygen in a 1:2:1 ratio. Examples: glucose (simple sugar), starch (complex carbohydrates).
- Lipids: Provide stored energy, insulation, and assist vitamin absorption, built from triglycerides.
- Proteins: Essential for growth and repair; made of amino acids forming polypeptides, broken down by enzymes into individual amino acids.
- Nucleic Acids: Store and carry genetic information, composed of nucleotides; includes DNA, not obtained from food sources.

Enzymes

Enzymes are proteins that act as catalysts, speeding up chemical reactions by lowering the activation energy needed.
Each enzyme is specific to its substrate, and enzyme activity can be influenced by temperature and pH.

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Description

Explore the fascinating history of cell study, from Robert Hooke's discovery of the term 'cell' to Rudolf Virchow's contributions on cell theory. This quiz covers the definition and types of cells, helping you understand the fundamental unit of life and its importance in biology.