Botany lecture notes

Difference Between Dicot and Monocot Stem (Anatomy): A Comparison Table

dicot stem vs monocot stem

Dicot Stem Vs Monocot Stem
Anatomical Similarities and Different Between Dicot Stem and Monocot Stem

(I). Similarities between dicot stem and monocot stem:

Ø  Epidermis is usually single layered in both dicots and monocots

Ø  Thick layer of cuticle present in both groups

Ø  Hypodermis is present in both the group (cell type varies)

Ø  Photosynthetic chlorenchymatous zone is present in the cortex of both dicots and monocots

Ø  Major portions of ground tissue is parenchymatous

Ø  Xylem and phloem are organized as vascular bundles in dicots and monocots

Ø  Vascular bundles are conjoint and collateral in both the groups

Ø  In monocots and dicots xylem and phloem composed of both proto- (protoxylem and protophloem) and meta- elements (metaxylem and metaphloem)

(II). Difference between dicot stem and monocot stem

Continue reading

Botany lecture notes

Lichens: General Characteristics (A Symbiotic Association Between Algae and Fungi)

Flavoparmelia caperata - lichen - Caperatflechte

Flavoparmelia: A Foliose Lichen (source wikipedia)

General Characteristics of Lichen

What are lichens?

Lichens are structurally organized permanent symbiotic association between fungi and algae. The fungal component of lichen is called mycobiont and the algal component of lichen is called phycobiont. Theophrastus (371 – 284 BC), who is known as the ‘Father of Botany’, for the first time used the term lichen to denote the superficial growth on tree barks. The branch of biology which deals with the study of lichen is called Lichenology and the one who studies is known as lichenologist. Acharius is known as the ‘Father of lichenology’.

Lichens are symbionts:

Lichens are symbiotic association between algae and fungi. The term Symbiosis (introduced by De-Bary, a mycologist) is used to specify the association or interaction of organisms where both partners are mutually benefitted. The fungus absorbs water and protects algae from unfavorable conditions such as drought and extreme temperature. The algal components, since they are autotrophs, in turn supplies organic food to fungus. This type of symbiosis is known as heliotism, a ‘master’ and ‘slave’ relationship.

Lichens do not show the morphology of fungi and algae:

Even though lichens are symbiotic association between algae and fungi, the vegetative morphology (plant body) of lichen neither resembles algal or fungal morphology. Fungal component is prominent vegetative part in lichen than algal component. Almost 90% of the plant body of lichen composed of fungal component. Due to the ill differentiated plant body, lichens are included in Thallophyta of Cryptogams along with algae and fungi.

Continue reading

mcq biology

MCQ on Membrane Lipids with Answer Key & Explanations (Biochemistry MCQ 010)

easybiologyclass, Archaebacterial ether lipids of plasma membrane

For details: Membrane lipids

MCQ on Membrane Lipids
Biochemistry MCQ-010
(Multiple Choice Questions in Biology / Life Science)
(Sample/Model/Practice Questions for JRF/NET Life Science Examination, ICMR JRF, DBT BET JRF, GATE, ICAR NET, PG Entrance)

(1). A genetic disorder caused by mutation in the hexosaminidase enzyme A which hydrolyze the GM2 to GM3 during membrane lipid turnover:

a.       Tay-Sachs syndrome
b.      Fabryi disease
c.       Gauche’s disease
d.      Niemann-Pick disease

(2). The simplest hydrophilic moiety present in the membrane lipid is:

a.       Phosphate group
b.      Hydroxyl group
c.       Amino group
d.      Glucose

(3). Which of the following cellular event can be best regulated by prostaglandins?        

a.       Synthesis of inter cellular cyclic AMP
b.      Synthesis of intra cellular cyclic AMP
c.       Synthesis of inter cellular cyclic GMP
d.      Synthesis of intra cellular cyclic GMP

(4). Which of the following statement is true regarding the solubility of steroids in biological fluids?

a.       Steroids and cholesterols are equally soluble
b.      Steroids are more soluble than cholesterol
c.       Cholesterol are more soluble than steroids
d.      Cholesterol and steroids are completely insoluble

(5). The potent molecular signal molecule Platelet Activating Factor (PAF) is an example for:

a.       Glycolipid
b.      Phospholipid
c.       Ether lipid
d.      Ceramide

Continue reading

Botany lecture notes

Difference Between Meristematic Tissues and Permanent Tissues in Plants

Meristem Vs Permanent Tissue

Meristematic Tissues Vs Permanent Tissues
Similarities and Difference between Meristematic Tissues and Permanent Tissues

Tissue is a group of cells with more or less common origin and doing a specific function. Plant tissues are broadly classified into two categories based on their capacity of cell division. They are (1) Meristematic tissues and (2) Permanent tissues. Meristem is a type of tissue system in plants, composed of a mass of undifferentiated cells and their primary function is to take part in the growth of plants. Permanent tissues are differentiated tissues doing specific functions such as conduction, providing mechanical support or carrying out photosynthesis etc. Permanent tissues are originated and differentiated from meristematic tissues. In this post we will discuss about the similarities and differences between two fundamentally different tissue systems namely Meristematic tissues and Permanent tissues.

Similarities between Meristematic Tissues and Permanent Tissues:

Ø  Both are tissue systems in plants

Ø  Both composed of group of cells, doing specific function

Ø  Meristematic tissues and some permanent tissues (parenchyma) are homogenous with a single type of cells

Difference between Meristematic Tissues and Permanent tissues:

(1). Meristematic Tissues:

(1). Meristematic tissue composed of undifferentiated cells

(2). Meristems will be always a simple tissue, composed of only one type of cells

(3). Cells are always living

(4). Cells always contain dense cytoplasm

(5). Cells always contain prominent nucleus

(6). Cells divide very rapidly

Continue reading

Botany lecture notes

What are the Characteristics of Meristems & Meristematic Cells?

Mitosis (261 14) Pressed; root meristem of onion (cells in prophase, anaphase)

Meristematic Cells of Root Apex Showing Cell Division (source wikipedia)

What are Meristems?

Meristem is a group of plant cells that remain in a continuous state of division. It is a tissue system in plants called meristematic tissue. The term meristem was proposed by Karl Nägeli from a Greek word ‘merizein’ which means ‘to divide’. The meristem composed of rapidly dividing undifferentiated mass of cells. Meristems are usually found in the growing region of plant organs such as shoot apex and root apex. Usually meristem originates from the embryonic cells. The primary function of meristem is to assist in plant growth and development. Meristematic cells are characteristically different from other differentiated cells in terms of many aspects. This post describes the characteristic features of meristematic cells in plants.

What are Characteristics of Meristems / Meristematic Tissues?

§.  Meristem composed of rapidly dividing cells

§.  Usually situated at the growing apex of plant parts (root apex or shoot apex)

§.  Meristematic cells are undifferentiated

Continue reading