Recent questions tagged ch3

In liverworts: 1. Asexual reproduction takes place by fragmentation of thalli 2. Sexual reproduction takes place by formation of gemmae 3. Gemmae are green, unicellular, buds 4. Gemmae develop in small receptacles - gemma cups located on the thalli. 5. The gemmae become detached from the parent body and germinate to form new individuals. Regarding 1,2,3,4 and 5:

asked Jan 6, 2014 by pady_1

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1. Mosses are some of the first organisms to colonise rocks 2. Mosses decompose rocks making the substrate suitable for the growth of higher plants. 3. Mosses form dense mats on the soil, they reduce the impact of falling rain and prevent soil erosion. Regarding 1,2 and 3:

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In Bryophytes: 1. The zygotes produce a multicellular body called a sporophyte. 2. The sporophyte is free-living 3. Some cells of the sporophyte undergo division to produce diploid spores. 4. These spores germinate to produce gametophyte.

asked Jan 6, 2014 by pady_1

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Regarding sexual reproduction in Bryophytes : 1. The female *** organ called archegonium is pyriformin shape 2. Archegonium produces a single egg. 3. The antherozoids are released into water where they come in contact with archegonium. 4. An antherozoid fuses with the egg to produce the zygote. 5. Zygotes undergo reduction division immediately.

asked Jan 6, 2014 by pady_1

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Regarding Bryophytes : 1.The plant body is thallus-like and prostrate or erect 2. The plant body is attached to the substratum by unicellular or multicellular rhizoids 3. They have true roots, stem or leaves. 4. They may possess root-like, leaf-like or stem-like structures. 5. The main plant body of the bryophyte is diploid.

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Regarding Rhodophyceae: 1. Majority of them are marine 2. Greater concentrations of Rhodophyceae are found in the warmer areas 3. They occur in well-lighted regions close to the surface of water 4. They can not grow at great depths in oceans where relatively little light penetrates

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Regarding the members of phaeophyceae or brown algae: 1. Vegetative reproduction takes place by fragmentation. 2. Sexual reproduction in most brown algae is by biflagellate zoospores. 3. Zoospores are pear-shaped and have two equal laterally attached flagella

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Regarding the members of phaeophyceae or brown algae: 1. possess chlorophyll a, c, carotenoids and xanthophylls. 2. Food is stored as complex carbohydrates, which may be in the form of laminarin or mannitol. 3. The vegetative cells have a cellulosic wall. 4. cellulosic wall usually covered on the outside by a gelatinous coating of algin. 5. The protoplast contains, in addition to plastids, a centrally located vacuole and nucleus.

asked Jan 6, 2014 by pady_1

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In Chlorophyceae: 1. Vegetative reproduction usually takes place by fragmentation or by formation of different types of spores. 2. Asexual reproduction is by non flagellated zoospores produced in zoosporangia. 3. Zoospores produced in zoosporangia. 4. The sexual reproduction shows considerable variation 5. Sexual reproduction may be isogamous, anisogamous or oogamous.

asked Jan 6, 2014 by pady_1

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In Chlorophyceae: 1. The pigments are not localised in chloroplasts. 2. The chloroplasts may be discoid, plate-like, reticulate, cup-shaped, spiral or ribbon-shaped in different species. 3. Most of the members have one or more storage bodies called pyrenoids located in the chloroplasts. 4. Pyrenoids contain only starch. 5. Some algae may store food in the form of cholesterol.

asked Jan 6, 2014 by pady_1

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1. Vegetative reproduction is by fragmentation. 2. Each fragment develops into a thallus. 3. Asexual reproduction is by the production of different types of spores, the most common - oospores. 4. The spores are non flagellated and on germination give rise to new plants.

asked Jan 6, 2014 by pady_1

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1. Numerical Taxonomy which is now easily carried out using computers is based on all observable characteristics. 2. Number and codes are assigned to all the characters and the data are then processed. 3. Some important characters are given more importance 4. Cytological information like chromosome number are aslo included 5. At the same time hundreds of characters can be considered.

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1. Fungi, and members of the Monera and Protista having cell walls have now been excluded from Plantae 2. Earlier classifications also have placed them in Plantae 3. The cyanobacteria that are also referred to as blue green algae are not ‘algae’ any more. Regarding 1,2 and 3:

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Assertion (A): At puberty only 60,000-80,000 primary follicles are left in each ovary. Reason (R): A large number of primary follicles degenerate during the phase from birth to puberty. Regarding (A) and (R):

asked Jan 3, 2014 by pady_1

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Regarding Oogenesis choose the incorrect one :

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1. The seminal plasma along with the sperms constitute the semen. 2. The functions of male *** accessory ducts and glands are maintained by the testicular hormones (androgens). Regarding 1 and 2 :

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Middle piece of a sperm :

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Microscopic structure of a sperm is composed of

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Follicle stimulating hormone (FSH) :

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Luteinising hormone (LH) :

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The increased levels of GnRH :

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1. Spermatogenesis starts at the age of puberty due to significant increase in the secretion of gonadotropin releasing hormone (GnRH). 2. GnRH is a pituitary hormone.

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1. Each spermatogonium contains 46 chromosomes. 2. Secondary spermatocytes have 23 chromosomes each. Regarding 1 and 2 :

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The spermatogonia -

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The primary *** organs –

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1. The hymen is often torn during the first coitus. 2. However the presence or absence of hymen is not a reliable indicator of virginity or sexual experience. Regarding 1 and 2 :

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1. The opening of the ** is often covered partially by a membrane called hymen. 2. The is a tiny finger-like structure which lies at the upper junction of the two * minora below the urethral opening. Regarding 1 and 2 :

asked Jan 3, 2014 by pady_1

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The female external genitalia includes all except:

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1. The endometrium undergoes cyclical changes during menstrual cycle 2. Myometrium exhibits strong contraction during delivery of the baby. Regarding 1 and 2 :

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Regarding uterus - choose the incorrect one:

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Regarding Fallopian tubes - choose the incorrect one :

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The female accessory ducts is / are constituted by:

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1. Each ovary is covered by a thin epithelium which encloses the ovarian stroma. 2. The stroma is divided into two zones $–$ a peripheral cortex and an inner medulla. Regarding 1 and 2 :

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Regarding Ovaries - choose the correct answer :

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The female reproductive system consists :

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The secretions of ______ helps in the lubrication of the *****.

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Secretions of male accessory glands :

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The male accessory glands include :

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1. The enlarged end of * called the glans * 2. It is covered by a loose fold of skin called foreskin. Regarding 1 and 2 :

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The male *** accessory ducts :

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Choose the incorrect one regarding male reproductive system :

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Choose and fill in the blanks in respective order: The seminiferous tubules of the testis open into the ____ through _ . The _ leave the testis and open into ______ located along the posterior surface of each testis.

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The male *** accessory ducts include

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Leydig cells :

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The region outside the seminiferous tubule is called interstitial space and contains __

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1. The male germ cells undergo mitotic divisions finally leading to sperm formation 2. Sertoli cells provide nutrition to the germ cells. Regarding 1 and 2 :

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Each seminiferous tubule is lined by two types of cells called and __

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1. Each testicular lobule contains one to three highly coiled seminiferous tubules 2. In seminiferous tubules sperms are produced. Regarding 1 and 2 :

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Incorrect statement regarding adult testes is:

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The male reproductive system includes all except :

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