History of Plant Classification

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Questions and Answers

What does the Scanning Electron Microscope (SEM) primarily use to produce images?

Beam transmission (correct)

X-rays

Ultraviolet light

Infrared light

Which component of the microscope connects the base to the tube?

Body tube (correct)

Substage

Arm

Stage

What is the purpose of the coarse adjustment knob in a microscope?

To control lighting in the substage

To fine-tune focus in low power

To initially focus the specimen (correct)

To focus using high power objectives

Which objective lens has the highest magnifying power?

Oil immersion objective Signup and view all the answers

What is the function of the Abbe condenser in a microscope?

To focus light onto the specimen Signup and view all the answers

How do the stage clips function in a microscope?

They support the slide securely Signup and view all the answers

Which part of the microscope allows the user to change from one objective lens to another?

Nosepiece Signup and view all the answers

What is the primary difference between the high power objective and low power objective?

Magnification level Signup and view all the answers

Who is known as the Father of Taxonomy?

Carolus Linnaeus Signup and view all the answers

Which botanist first published a natural classification of flowering plants?

Arthur Cronquist Signup and view all the answers

What did Gaspard Bauhin contribute to plant taxonomy?

Grouped morphologically similar species Signup and view all the answers

Which of the following statements about Charles Edwin Bessey is correct?

He introduced the systematic study of plant morphology. Signup and view all the answers

Who wrote ‘Diversity and Classification of Flowering Plants’?

Armen Takhtajan Signup and view all the answers

What was the main focus of Antoine-Laurent de Jussieu's work?

The systematic arrangement of plants in botanical gardens Signup and view all the answers

Which system of classification is associated with Adolf Engler and Karl Prantl?

Phylogenetic classification Signup and view all the answers

In what year did Gaspard Bauhin publish significant work related to plant classification?

1624 Signup and view all the answers

What is the main function of the Rough Endoplasmic Reticulum (RER)?

Protein synthesis Signup and view all the answers

What role do peroxisomes play in cellular processes?

Carrying out oxidative reactions Signup and view all the answers

Which of the following best describes the major difference between Rough and Smooth Endoplasmic Reticulum?

RER has ribosomes attached; SER does not. Signup and view all the answers

What is the primary function of the enzyme catalase within peroxisomes?

To convert hydrogen peroxide to oxygen and water Signup and view all the answers

How are plastids significant in plant cells?

They contain circular DNA and assist in food production. Signup and view all the answers

What is the structure of ribosomes in a cell?

Dispersed in the cytoplasm or attached to the ER Signup and view all the answers

What characterizes the Smooth Endoplasmic Reticulum?

It assists in lipid synthesis. Signup and view all the answers

What aspect of the maturing face of the Golgi apparatus is crucial for germination in oily seeds?

It releases golgi vacuoles with modified enzymes. Signup and view all the answers

What is the primary role of microtubules in cells?

Facilitate cell division and morphogenesis Signup and view all the answers

What characteristic defines heterochromatin?

Tightly packed and less accessible Signup and view all the answers

Which part of the nucleus is directly involved in ribosomal RNA synthesis?

Nucleolus Signup and view all the answers

What is the significance of the nuclear pore complexes?

Control the exchange of materials between the nucleus and cytoplasm Signup and view all the answers

What does the nuclear envelope primarily consist of?

An outer and an inner membrane Signup and view all the answers

Which function does the nucleoplasm serve?

Involved in transport processes within the nucleus Signup and view all the answers

What is one role of the underlying nuclear lamina?

Provide structural support to the nucleus Signup and view all the answers

What characterizes the nuclear envelope during active transcription stages?

Frequently interrupted by nuclear pore complexes Signup and view all the answers

What is the primary function of parenchyma tissue in higher plants?

Stores food and waste Signup and view all the answers

Which of the following cells compose the endodermis?

Closely packed, thin-walled cells Signup and view all the answers

Where do lateral roots originate in relation to the stele?

Within the pericycle Signup and view all the answers

What characteristic of meristematic tissues distinguishes them from other tissue types?

Cells actively divide Signup and view all the answers

Which of the following statements about the fibrous root system is correct?

It stabilizes soil and prevents erosion. Signup and view all the answers

What type of cells make up the majority of the pericycle?

Parenchyma cells Signup and view all the answers

What structures are found opposite the protoxylem in the endodermis?

Passage cells Signup and view all the answers

How do parenchyma cells appear when they are newly produced?

Spherical and uniform in size Signup and view all the answers

Study Notes

History of Classification

Gaspard Bauhin grouped morphologically similar species together in the same genus.
Carolus Linnaeus (Father of Taxonomy) developed the binomial system of nomenclature for efficiently grouping and naming organisms. He wrote "Species Plantarum" in 1753.
Antoine-Laurent de Jussieu organized plants systematically in botanical gardens based on their characteristics.
Charles Edwin Bessey introduced the phylogenetic system of classification to the US and focused on the systematic study of plant morphology.
Arthur Cronquist wrote "The Evolution and Classification of Flowering Plants" in 1988, which was a groundbreaking work in plant classification.
Armen Takhtajan is considered one of the greatest botanists in the world, writing about the evolution of plants and publishing "Diversity and Classification of Flowering Plants" in 1997.
Adolf Engler and Karl Prantl developed a popular system of classification based on the phylogenetic system.

Microscopes

Scanning Electron Microscope (SEM) uses beam transmission to produce images by detecting secondary electrons. It can magnify objects up to 10,000 times their original size.
Mechanical Parts of the Microscope:
- Base: U or V-shaped, provides a stable foundation for the microscope.
- Arm: Connects the base and the tube, serving as a handle for carrying the microscope.
- Stage: Holds the slide containing the specimen, with an opening in the center for light to pass through.
- Stage Clips: Secure the specimen on the stage.
- Substage: Located below the stage, holds the Abbe condenser and the iris diaphragm.
- Body Tube: Connects the objective to the eyepiece, allowing light to pass from the objective to the eyepiece.
- Coarse Adjustment: Used for low power objective (LPO) focusing.
- Fine Adjustment: Used for high power objective (HPO) focusing.
- Maturing Face: Also called the Trans face or concave, where vesicles start to swell and are released.
Magnifying Parts of the Microscope:
- Eyepiece or Ocular: Detachable cylinder located at the top of the tube with a pointer that rotates.
- Objectives: Two or three objectives attached to the revolving nosepiece.
  - Scanner Objective: Shortest cylinder with a large opening for low magnification (marked "5x").
  - Low Power Objective: Used to observe the general outline of the specimen.
  - High Power Objective: Longest cylinder with a small opening for higher magnification, used to study detailed parts of the specimen.
  - Oil Immersion Objective: Important for the germination of oily seeds.

Cell Structures

Endoplasmic Reticulum (ER): A network of narrow tubes and sheets of membrane throughout the cytoplasm.
- Rough Endoplasmic Reticulum (RER): Has ribosomes attached and is involved in protein synthesis.
- Smooth Endoplasmic Reticulum (SER): Does not have ribosomes attached and is involved in lipid synthesis.
Ribosomes: Responsible for protein synthesis, found dispersed in the cytoplasm or attached to the ER.
Golgi Apparatus: Packages and modifies proteins and enzymes, sorts them into vesicles, and releases them into the cytoplasm.
Peroxisomes: Detoxify some products of photosynthesis, specialized for oxidative reactions using molecular oxygen. They contain the enzyme catalase.
Enzyme Catalase: Detoxifies peroxides through chemical reactions, converting it to oxygen and water.
Plastids: Found in plants and algae, surrounded by inner and outer membranes. Have circular DNA not associated with histones.
- Stroma: Inner fluids that encircle the grana and thylakoids.
- Chloroplasts: Disc-shaped, contain chlorophyll for photosynthesis.
- Chromoplasts: Contain different pigments that give plants their colors.

Nucleus

Nucleus: The cell’s command center, surrounded by the nuclear envelope, filled with nucleoplasm.
Four Main Parts of the Nucleus:
- Nuclear Envelope: Composed of a membrane perforated by numerous pores.
- Nucleoplasm: Granular fluid inside the nucleus, a type of protoplasm.
- Chromatin: Contains DNA and proteins, involved in protein synthesis.
- Nucleolus: The largest and most prominent domain in the nucleus, where ribosomal RNA synthesis occurs.
Heterochromatin: Tightly packed, less accessible for transcription, restrains the activity of transposable elements.
Underlying Nuclear Lamina: A fibrous meshwork that provides structural support to the nucleus.
Nuclear Pore Complexes: Large protein complex controlling the exchange of components between the nucleus and the cytoplasm.

Plant Tissues

Meristematic Tissues: Cells actively divide and are responsible for the production of new cells.
- Location:
  - Apical Meristem: Found at the tips of roots and shoots, responsible for growth in length.
  - Lateral Meristem: Located along the sides of roots and stems, responsible for growth in width.
  - Intercalary Meristem: Found at the nodes of stems, responsible for growth in length.
Permanent Tissues: Mature cells that have lost the ability to divide.
- Simple Permanent Tissues:
  - Parenchyma: The most abundant tissue type, responsible for food and waste storage.
  - Collenchyma: Provides structural support and flexibility, commonly found in stems and leaves.
  - Sclerenchyma: Provides strength and rigidity to the plant, found in stems, roots, and leaves as fibers and sclereids.
- Complex Permanent Tissues:
  - Xylem: Transports water and minerals upwards from the roots.
  - Phloem: Transports food downwards from the leaves to other parts of the plant.

Water Relations in Cells and Tissues

Water: Involved in transport processes within cells.
Endodermis: The innermost layer of the cortex, a single layer of closely packed barrel-shaped cells with no intercellular spaces. Passage cells, located opposite the protoxylem, are thin-walled.
Stele or Vascular Cylinder: Occupies the central portion of the root, consisting of the pericycle and vascular tissues.
Pericycle: Lies internal to the endodermis, a single layer of thin-walled parenchyma cells.
Root System:
- Taproot System: Has a main root with lateral branches. Common in dicot plants.
- Fibrous Root System: Consists of a network of fine roots, common in monocot plants. Important for stabilizing soil and preventing erosion.
- Lateral Roots: Originating from the pericycle.
Radicle: The embryonic root, which emerges first from the seed.

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Description

Explore the evolution of plant classification from Gaspard Bauhin to modern botanists. This quiz covers key figures and their contributions, including Linnaeus's binomial nomenclature and the phylogenetic system introduced by Bessey and Takhtajan. Test your knowledge on how these classifications have shaped our understanding of plant diversity.