Question
Write a short note on endosperm development.
✓
Answer
→ Endosperm development precedes embryo development.
→ The primary endosperm cell divides repeatedly and forms a triploid endosperm tissue.
→ The cells of this tissue are filled with reserve food materials and are used for the nutrition of the developing embryo.
→ In the most common type of endosperm development, the PEN undergoes successive nuclear divisions to give rise to free nuclei. This stage of endosperm development is called free-nuclear endosperm.
→ Subsequently cell wall formation occurs and the endosperm becomes cellular.
→ The number of free nuclei formed before cellularisation varies greatly.
→ The coconut water from tender coconut that you are familiar with, is nothing but free- nuclear endosperm (made up of thousands of nuclei) and the surrounding white kernel is the cellular endosperm.
→ Endosperm may either be completely consumed by the developing embryo (e.g., pea, groundnut, beans) before seed maturation or it may persist in the mature seed (e.g. castor and coconut) and be used up during seed germination.
→ The primary endosperm cell divides repeatedly and forms a triploid endosperm tissue.
→ The cells of this tissue are filled with reserve food materials and are used for the nutrition of the developing embryo.
→ In the most common type of endosperm development, the PEN undergoes successive nuclear divisions to give rise to free nuclei. This stage of endosperm development is called free-nuclear endosperm.
→ Subsequently cell wall formation occurs and the endosperm becomes cellular.
→ The number of free nuclei formed before cellularisation varies greatly.
→ The coconut water from tender coconut that you are familiar with, is nothing but free- nuclear endosperm (made up of thousands of nuclei) and the surrounding white kernel is the cellular endosperm.
→ Endosperm may either be completely consumed by the developing embryo (e.g., pea, groundnut, beans) before seed maturation or it may persist in the mature seed (e.g. castor and coconut) and be used up during seed germination.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Read the following and answer any four questions from (i) to (v) given below:
A 23 year old Sahil has been diagnosed with an infection of reproductive tract caused by bacteria. He complains about burning sensation during urination, pus-containing discharge and pain around genitalia. This infection has incubation period of 2-5 days but can be cured.
A 23 year old Sahil has been diagnosed with an infection of reproductive tract caused by bacteria. He complains about burning sensation during urination, pus-containing discharge and pain around genitalia. This infection has incubation period of 2-5 days but can be cured.
- From which disease is Sahil suffering?
- Chlamydiasis.
- Herpes.
- Gonorrhoea.
- Syphilis.
- Which among the following reproductive tract infections is transmitted by bacteria?
- Trichomoniasis.
- Chancroid.
- Genital warts.
- Both (a) and (b).
- Which mode of treatment would be useful for Sahil?
- Cryosurgery.
- Use of Podophyllum preparation.
- Use of antibiotic ampicillin.
- It cannot be treated.
- What technique was used to diagnose Sahil's disease?
- Gram staining of discharge and culture.
- ELISA Test.
- Antibody detection.
- Antigen test.
- Find the odd one out.
- Treponema pallidum.
- Neisseria gonorrhoeae.
- Haernophilus ducreyi.
- Trichomonas vaginalis.
Explain exponential growth equation with well labeled diagram.###Explain exponential growth.
Read the following text carefully and answer the questions that follow:
A healthy immune system defends the body against disease and infection. But if the immune system malfunctions, it mistakenly attacks healthy cells, tissues, and organs. Called autoimmune disease, these attacks can affect any part of the body, weakening bodily function and even turning life-threatening.
i. Why are autoimmune diseases called degenerative diseases? (1)
ii. Name the autoimmune disease of body muscles. (1)
iii. Which types of immunity is provided by T-lymphocytes? (2)
OR
Which immune cells form humoral immune system? (2)
A healthy immune system defends the body against disease and infection. But if the immune system malfunctions, it mistakenly attacks healthy cells, tissues, and organs. Called autoimmune disease, these attacks can affect any part of the body, weakening bodily function and even turning life-threatening.
i. Why are autoimmune diseases called degenerative diseases? (1)
ii. Name the autoimmune disease of body muscles. (1)
iii. Which types of immunity is provided by T-lymphocytes? (2)
OR
Which immune cells form humoral immune system? (2)
Read the following and answer any four questions from (i) to (v) given below:
The first menstruation is called menarche, that usually occurs between 12 and 15 years. In human females, menstruation is repeated at an average interval of about 28/29 days and is called menstrual cycle. It is regulated by certain hormones, as pituitary gland is stimulated by releasing factors produced in the hypothalamus. The hormones produced by pituitary gland influence the ovaries. The hormones secreted by the ovaries affect the walls of the uterus.
The first menstruation is called menarche, that usually occurs between 12 and 15 years. In human females, menstruation is repeated at an average interval of about 28/29 days and is called menstrual cycle. It is regulated by certain hormones, as pituitary gland is stimulated by releasing factors produced in the hypothalamus. The hormones produced by pituitary gland influence the ovaries. The hormones secreted by the ovaries affect the walls of the uterus.
- The breakdown of endometrium is characteristic of:
- Proliferative phase.
- Luteal phase.
- Ovulatory phase.
- Menstrual phase.
- Which days of the menstrual cycle marks the proliferative phase?
- 1-5
- 15-28
- 6-13
- 10-14
- Which of the following occurs during secretory phase?
- Empty Graafian follicle changes into corpus luteum.
- Primary follicle changes into Graafian follicle.
- Endometrium rebuilds and estrogen secretion increases.
- LH surge, inducing release of an ovum.
- Identify the hormones that attain peak level during ovulatory phase.
- FSH.
- Progesterone.
- LH.
- Both (a) and (c).
- Withdrawal of which hormone causes degeneration of corpus luteum?
- FSH.
- LH.
- Progesterone.
- Estrogen.
Explain innate immunity in detail
Explain Competition as a population Interaction with suitable examples.
Read the following text carefully and answer the questions that follow:
Cleavage is the series of rapid mitotic divisions in zygote and forms blastula. The 2, 4, 8, 16 daughter cells are called blastomeres. Embryo with 64 blastomeres is known as blastocyst and has blastocoel cavity. Blastocyst gets implanted in uterine wall and leads to pregnancy.
i. Why the cells of the inner cell mass of blastocyst are called stem cells? (1)
ii. At which stage of embryonic development trophoectoderm develops? (1)
iii. What is the site of implantation? (2)
OR
What is the correct sequence of various structures formed during embryonic development? (2)
Cleavage is the series of rapid mitotic divisions in zygote and forms blastula. The 2, 4, 8, 16 daughter cells are called blastomeres. Embryo with 64 blastomeres is known as blastocyst and has blastocoel cavity. Blastocyst gets implanted in uterine wall and leads to pregnancy.
i. Why the cells of the inner cell mass of blastocyst are called stem cells? (1)
ii. At which stage of embryonic development trophoectoderm develops? (1)
iii. What is the site of implantation? (2)
OR
What is the correct sequence of various structures formed during embryonic development? (2)
Read the following and answer any four questions from (i) to (v) given below: Within a region, species richness increases with increasing explored area, but only upto a limit. TI1e given graph explains this relationship. 
→ - What does the given figure show?
- Rivet-popper hypothesis.
- Species-area relationship.
- Proportionate number of species of major taxa.
- $\alpha-\text{ecological diversity }$
- Equation for relationship (A) between species richness and area is:
-
$\log\text{ S}=\log\text{ C}+\text{Z }\log\text{ A}$
-
$\log\text{ C}=\log\text{ S}+\text{Z }\log\text{ A}$
-
$\text{Z }\log\text{ A}=\log\text{ S}+\log\text{ C}$
-
$\log\text{ S}=\log\text{ C}+\log\text{ A}$
- What is the value of slope of line or regression coefficient Z for frugivorous birds?
- 0.1 - 0.2
- 1.15
- 0.01 - 0.1
- 0.6 - 1.2
- The shape of curve for relationship between species richness and areas for wide variety of taxa is:
- Straight line.
- Parabola.
- Rectangular hyperbola.
- Bell shaped.
- Who gave this concept of increase in species richness with increasing offered area?
- Humboldt.
- Odum.
- Edward Wilson.
- Paul Ehrlich.
Explain with diagram - Hershey and Chase experiment.###On the basis of experimental proof explain the diagram that DNA is genetic material.###How did Hershey and Chase differentiate between DNA and protein in their experiment while proving that DNA is the genetic material?
Write a note on Mechanism of DNA replication