Germ Layers

Q. Endosperm development precedes embryo development. Why?

Q. Why does endosperm development precedes embryo development?

Q. Function of bulbourethral gland is/are:

1. Lubricate the penis
2. Increase the motility of sperm
3. More efficient sperm transfer
4. All of the above

Q.

Nourishment to the developing embryo is provided by which part of the ovule?

Q.

What is the first organ to develop in the embryo?

Q.

Study the given diagram:


A is an embryonic stage which gets transformed into B, which in turn gets implanted in the endometrium in human females.

a) Identify A , B and its parts C and D.
b) State the fate of C and D in the course of embryonic developement in humans. [3 marks]

Q.

What is cephalization?

Q.

The animals possessing the following types of germ layers (a and b) are _____________and _____________ respectively.

1. diploblastic, triploblastic

2. triploblastic, diploblastic

3. diploblastic, diploblastic

4. triploblastic, triploblastic

Q.

Do humans have Gill slits in embryonic stage? If they have Gill slits what does it become in adults?

Q. In the case of adventive polyembryony, if an embryo develops from the synergid and another from the nucellus, then synergid embryo will be ___________ and the nucellar embryo will be __________ .

1. haploid, haploid
2. diploid, diploid
3. haploid, diploid
4. diploid, haploid

Q.

Do humans have a notochord?

Q. A body cavity which is lined by mesoderm is called

1. Coelom
2. Blastocoel
3. Pseudocoel
4. Haemocoel

Q. Human beings have

1. two germ layers - ectoderm and endoderm
2. two germ layers - ecotoderm and mesoderm
3. two germ layers - mesoderm and endoderm
4. three germ layers - ectoderm, mesoderm and endoderm

Q.

The main haematopoietic organ in human embryo is

1. Bone marrow

2. Spleen

3. Kidney

4. Liver

Q.

What is rudimentary notochord?

Q.

The membranous covering of the heart is

1. Meninges

2. Pericardium

3. Pleura

4. Peritoneum

Q.

Differentiate between a diplobastic and a triploblastic animal.

Q.

What does notochord become in humans?

Q.

What would happen if the diencephalon is damaged?

Q. Match the germ layers.

1. Outer germ layer
2. Two germ layers
3. Three germ layers
4. Inner germ layer

Q. Uterus is a female accessory duct. Cervix is a part of uterus .So why cervix is not considered a female accessory duct ?

Q. The ratio between the number of synergids and antipodals in an embryosac is

1. 1 : 2
2. 2 : 5
3. 3 : 4
4. 2 : 3

Q.

Does trophoblast become placenta?

Q.

Most organisms have the capacity of regeneration in some or the other way.

1. True
2. False

Q.

Diploblastic animals possess

1. Differentiated ectoderm

2. Differentiated endoderm

3. Undifferentiated mesoglea

4. All of these

Q. Read the given passage and answer the question below.

The reproductive cycle, in female primates, called the menstrual cycle, comprises 28 days in a healthy female. Primata is the order to which monkeys, apes and human beings belong. The duration of the menstrual cycle varies in different females as it is dependent upon a number of factors. However, the average duration amounts to around 28 days.

At which stage in the menstrual cycle does the proliferative phase occur?
[1 mark]

1. Days 1 - 5
2. Days 5 - 14
3. Days 15 - 28
4. Days 17 - 21

Q. Which among the following is not a character of apomixis?

1. Does not involve gamete formation
2. A type of asexual reproduction
3. Unreduced egg cell develops parthenogenetically into an embryo
4. Fosters the propagation of new genes in a population

Q. Liver and pancreas develop from

1. Ectoderm
2. Mesoderm
3. Endoderm
4. Both A and B

Q. In development, nervous system (brain, spinal cord, nerve cells) is

1. Ectodermal
2. Endodermal
3. Ectomesoderma
4. Endomesodermal

Q. Liver and pancreas develops from

1. Ectoderm
2. Mesoderm
3. Ecto-mesoderm
4. Endoderm