Recent questions tagged reproduction

Description : DESCRIBE THE PROCESS OF OOGENESIS IN HUMAN FEMALE AND DIFFERENTIATE IT WITH SPERMATOGENESIS ON THE BASIS OF TIME OF INITIATION AND THE PRODUCTS FORMED.

Last Answer : ANS. OOGENESIS : DIAGRAMMATIC REPRESENTATION AS GIVEN IN NCERT. DIFFERENCES BETWEEN : OOGENESIS SPERMATOGENESIS (i) STARTS DURING FOETAL LIFE (i) STARTS DURING PUBERTY (ii)PRODUCTS: OVUM (ii) SPERMS

Description : (a) IN WHICH PART OF HUMAN FEMALE REPRODUCTIVE SYSTEM DO THE FOLLOWING EVENTS TAKE PLACE. (i) RELEASE OF FIRST POLAR BODY (ii) RELEASE OF SECOND POLAR BODY (iii) FERTILISATION (iv) IMPLANTATION (b) NAME TWO HORMONES SECREATED ONLY DURING PREGNANCY.

Last Answer : ANS (a) (i) OVARY (ii) FALLOPIAN TUBE (iii) AMPULLA-ISTHAMUS JUNCTION OF FALLOPIAN TUBE (iv) ENDOMETRIUM LINING OF UTERUS (b) HUMAN CHORIONIC GONADOTROPIN AND HUMAN PLACENTAL LACTOGEN

Description : WHAT IS APOMIXIS? DESCRIBE ITS IMPORTANCE?

Last Answer : ANS. IT IS THE PROCESS OF DEVELOPMENT OF SEEDS WITHOUT FERTILISATION. EXAMPLE: SOME SPECIES OF ASTERACEAE AND GRASSES. IMPORTANCE: APOMICTIC GENES CAN BE INTRDUED IN HYBRID SEED INDUSTRY.

Description : (A) MENTION ANY FOUR STRATEGIES ADOPTED BY FLOWERING PLANTS TO PREVENT SELF-POLLINATION. (B) DEFINE THE TERM EMASCULATION.

Last Answer : ANS.(a) (i) SELF INCOMPATIBILITY (ii) PRODUCTION OF UNICELLULAR FLOWERS (iii) ANTHERS AND STIGMA ARE PLACED AT DIFFERENT POSITIONS. (iv) MATURATION OF ANTHER AND STIGMA IS NOT ... EMASCULATION: REMOVAL OF ANTHER BEFORE MATURITY SO AS TO ENSURE CROSS POLLINATION IN SELF POLLINATING FLOWERS.

Description : DESCRIBE THE CONTRACEPTIVE ACTIONS OF IUDs.

Last Answer : ANS. (i) INCREASES PHAGOCYTOSIS OF SPERMS (ii) SUPPRESS SPERM MOTILITY (iii) SUPPRESS FERTILISING CAPACITY OF SPERMS (iv) MAKES CERVIX HOSTILE TO SPERMS.

Description : DIFFERENTIATE BETWEEN MORULA AND BLASTULA STAGES OF MAMMALIAN EMBRYO.

Last Answer : ANS. MORULA: (i) 8 TO 16 CELLED STAGE EMBRYO (ii) SOLID WITHOUT ANY CAVITY BLASTULA: (i) 32 CELLED STAGE EMBRYO. (ii) HOLLOW WITH A CAVITY CALLED BLASTOCOEL

Description : WHAT IS CORPUS LUTEUM ? UNDER WHAT CONDITIONS DOES IT UNDERGO DEGENERATION ?

Last Answer : ANS. THE CORPUS LUTEUM IS FORMED IN THE MAMMALIAN OVARY FROM RUPTURED GRAAFIAN FOLLICLE AFTER OVULATION. IT DEGENERATES IN THE ABSENCE OF FERTILISATION, AS THE LEVEL OF FSH AND LH DROPS.

Description : WRITE THE FUNTION OF EACH OF THE FOLLOWING: (a) MIDDLE PIECE OF HUMAN SPERM (b) LUTEINIZING HORMONE IN HUMAN MALES

Last Answer : ANS. (a) PROVIDES ENERGY FOR MOVEMENT DUE TO PRESENCE OF MITOCHONDRIA. (c) STIMULATES SYNTHESIS AND SECRETION OF ANDROGENS.

Description : STATE ONE ADVANTAGE AND ONE DISADVANTAGE OF CLEISTOGAMY.

Last Answer : ANS. ADVANTAGE: ASSURED SEED SET DISADVANTAGE: INBREEDING DEPRESSION.

Description : WHY IS THE PROCESS OF FERTILISATION IN A FLOWERING PLANT REFFERED TO AS DOUBLE FERTILISATION ?

Last Answer : ANS. DOUBLE FERTILISATION= SYNGAMY + TRIPLE FUSION SYNGAMY= ONE MALE GAMETE + EGG--- ZYGOTE(n) TRIPLE FUSION= ANOTHER MALE GAMETE+ POLAR NUCLEI-PRIMARY ENOSPERM NUCLEUS(3n)

Description : WHEN DO THE OOGENESIS AND THE SPERMATOGENESIS INITIATE IN HUMAN FEMALES AND MALES RESPECTIVELY ?

Last Answer : ANS. OOGENESIS AT THE FOETAL LIFEAND SPERMATOGENISIS STARTS AT PUBERTY.

Description : WRITE THE LOCATION AND FUNCTION OF SERTOLI CELLS IN HUMANS.

Last Answer : ANS. IN THE SEMINIFEROUS TUBULES OF TESTIS, NOURISHES DEVELOPING SPERMS.

Description : AT WHAT STAGE IS THE MAMMALIAN EMBRYO IMPLANTED IN THE UTERUS ?

Last Answer : ANS. AT THE BLASTOCYST STAGE.

Description : NAME THE PROTECTIVE SUBSTANCE PRESENT IN THE POLLEN ENVELOPE TO TIDE OVER ADVERSE CONDITIONS.

Last Answer : ANS. SPOROPOLLENIN.

Description : NAME THE TYPE OF FLOWER WHICH FAVOURS CROSS POLLINATION.

Last Answer : ANS. CHASMOGAMOUS.

Description : WHAT IS PERISPERM ?

Last Answer : ANS. THE RESIDUAL NUCELLUS, WHICH PERSISTS IN THE SEEDS IS CALLED AS PERISPERM.

Description : NAME THE PHENOMENON AND ONE BIRD WHERE THE FEMALE GAMETE DIRECTLY DEVELOPS INTO A NEW ORGANISM.

Last Answer : ANS. PARTHENOGENESIS, TURKEY.

Description : WHY ARE DATE PALMS REFFERED TO AS DIOECIOUS ?

Last Answer : ANS. BECAUSE THEY HAVE UNISEXUAL FLOWERS BORNE ON SEPARATE PLANTS.

Description : WHAT TERM IS GIVEN BY YOU TO THE GROUP OF INDIVIDUALS WHICH ARE GENETICALLY AND MORPHOLOGICALLY IDENTICAL ?

Last Answer : ANS. CLONE

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