Homework Help for Biology

What is the functional unit of kidney?

A) alveoli 

B) nephron 

C)fetus

D) bacteria 

What is biology 

Give a short notes 

Pollination 

Give short answer 

1. Pollination?

Short notes on

microsporogenesis , microsporangia , microsporangium

Megasporangia and Megasporangium

What is rRNA?

1. Cell and Molecular Biology:

"Can you explain the process of DNA replication and its significance in cellular division?"

"What role do mitochondria play in cellular metabolism and energy production?"

2. Genetics:

"How do genetic mutations contribute to the development of diseases, and what are some examples?"

"Can you describe the difference between gene expression regulation in prokaryotes and eukaryotes?"

3. Ecology:

"How do environmental factors influence species distribution and community structure in an ecosystem?"

"What are the key concepts of biodiversity, and why is it crucial for ecosystem stability?"

4. Evolutionary Biology:

"How does natural selection contribute to the adaptation of species in different environments?"

"Can you provide examples of evolutionary convergence in animal species?"

5. Physiology:

"How do the endocrine and nervous systems work together to regulate body functions?"

"What are the physiological responses of the human body to long-term exercise?"

6. Microbiology:

"How do bacteria develop resistance to antibiotics, and what can be done to combat this issue?"

"What role do microbes play in human

health, particularly in the gut microbiome?"

Meaning of binomial nomenclature

Can I sell class 11 bio notes

1. what is polyhydroxyaldheyde?
2. what is biomolecule?
3. what is other name of carbohydrates?

full form of DNA?

what is ptsd

Pteridophytes Practical notes
Psilotum – Habit
The plant body is differentiated into a horizontal underground rhizome and an erect aerial stem.
The rhizome and aerial stem are dichotomously branched.
The stem bear numerous scaly leaves.
The fertile leaves are found on the upper parts of the stem and they bear trilobes spore bearing structures called synangia in their axils.
Psilotum – Stem T.S.
A transverse section of the aerial stem shows the epidermis, cortex and stele.
Epidermis is single layered with a thick cuticle.
The cortex is three zoned with outer chlorenchymatous, middle sclerenchymatous and inner parenchymatous cells.
The innermost layer of cortex is single layered endodermis followed by pericycle.
The stele is an actinostelic protostele with star shaped xylem surrounded by phloem.

Psilotum – Synangium C.S.
The sporophyte reproduces by means of spores and are produced in trilobed structures called synangia.
The synangia are formed on the axils of the fertile scale leaves.
In cross section, the synangia has 4-5 layered wall which covers three chambers or spore cavities containing spores.
The spores are homosporous.

Lycopodium cernuum – Habit
The plant body is a sporophyte differentiated into root, stem and leaves.
The stem is branched and the branching is dichotomous.
The leaves are all along the stem in spiral fashion and are extremely small.
The strobili or cone are present at the tips of branches.

Lycopodium Stem T.S.
The T.S. of stem shows three regions namely epidermis, cortex and stele.
Epidermis is made up of single layer of cutinised cells.
Cortex is heterogenous viz. outer parenchymatous, middle sclerenchymatous and inner parenchymatous regions.
Stele is surrounded by endodermis and pericycle.
The stele is a mixed protostele. The xylem and phloem are intermixed.

Lycopodium – Cone L.S.
A L.S. of the strobilus shows a central axis and the sporophylls on the either side.
The sporophylls are eligulate and bears a single sporangium on its adaxial surface.
The sporangium has multicellular stalk and covered by wall layers.
The spores are produced inside the sporangium and are homosporous.

Selaginella – Habit 
The plant body is a sporophyte differentiated into stem, root and leaves.
The branching of the stem is dichotomous or lateral.
The leaves are small and are arranged spirally.
Membranous outgrowth called ligules are present on the adaxial surface of the leaves.
At the forking of the branch in the stem, rhizophores are present.
The reproductive structures aggregate at the apices of the branches to form the cone or strobilus.

Selaginella – Stem T.S.
A transverse section of the stem shows three main regions namely epidermis, cortex and stele.
Epidermis is single layered. The cells are closely packed and stomata are absent.
Cortex is completely parenchymatous.
Stele is a protostele surrounded by endodermis and pericycle.
The endodermal cells are radially elongated and form trabeculae.
The stele is normally polystelic. usually, 2-3 steles are present.

Selaginella – Cone L.S.
A L.S. of the strobilus shows a central axis on which are spirally arranges sporophylls.
Each sporophyll bears a single stalked sporangium in its axils.
The sporangia are of two types megasporangia and microsporangia (Heterosporous).
Microsporangium bears numerous small microspores.
The megasporangium has usually 3-4 megaspores.

Gleichenia – Habit
Gleichenia have a creeping, dichotomously branched and long rhizome.
The fronds are compound leaves that fork multiple times, with the final leaf lobes ending in a pinnate arrangement 
At the bottom of the leaves, round, abaxial, and exindusiate sori is present.

Gleichenia – Rhizome T.S.
A T.S. of Gleichenia rhizome shows epidermis, cortex and stele.
The epidermis is single layered and continuous.
The cortex is differentiated into outer sclerenchymatous and inner parenchymatous cortex.
The stele is surrounded by endodermis and pericycle.
The stele is a mixed protostele.

Gleichenia – Spore producing structures
The spore producing structure is a sporangium and are homosporous.
4-15 sporangia present on the ventral surface of the sporophylls in sori.
Each sporangium is pear shaped, sessile, covered with a single layered jacket and contains numerous spores.

What is earth

What is taxonomy ?