Plus Two Zoology Practice Flashcards

Comprehensive vocabulary flashcards covering the key terms and concepts of Plus Two Zoology as presented in the Vidhyaposhini 2023-24 lecture notes.

Gametogenesis

The process of formation of Gametes.

Insemination

The transfer of gametes into the female genital tract.

Implantation

The attachment of a blastocyst to the uterine wall.

Gestation

The period of development of the embryo.

Parturition

The process of the delivery of the baby.

Scrotum

A pouch located outside the abdominal cavity that maintains a temperature $2-2.5^\circ\text{C}$ lower than the normal body temperature for spermatogenesis.

Sertoli cells

Cells located in the seminiferous tubules that give nourishment to the male germ cells.

Leydig cells

Also called interstitial cells, these are present outside seminiferous tubules and synthesise/secrete androgens.

Seminal plasma

Secretions from male accessory glands rich in fructose, $\text{Ca}$, and certain enzymes; also known as semen.

Fimbriae

Finger-like projections at the edges of the infundibulum that help in collecting the ovum during ovulation.

Endometrium

The glandular inner layer of the uterus that undergoes cyclical changes during the menstrual cycle.

Colostrum

The yellowish first milk produced in the mammary gland which contains $\text{Ig A}$ and provides immunity to the baby.

Acrosome

A cap-like structure on the sperm head designed to penetrate the ovum.

Menarche

The occurrence of the first menstruation.

Menopause

The stopping of menstruation.

Corpus luteum

A structure formed in the ovary during the luteal phase that secretes large amounts of progesterone to maintain the endometrium.

Morula

The embryo consisting of $8-16$ blastomeres.

Amniocentesis

A procedure to study the chromosomal pattern in amniotic fluid to determine fetal sex or identify chromosomal disorders.

Saheli

A new oral contraceptive for females developed by scientists at the Central Drug Research Institute (CDRI) in Lucknow, India.

Vasectomy

A male sterilization method where a small portion of the vas deferens is removed or tied up.

GIFT

Gamete Intra Fallopian Transfer; an assisted reproductive technology.

Test cross

Crossing the $F_1$ hybrid with the recessive parent to find out the genotype of an unknown individual.

Pleiotropism

A phenomenon where a single gene produces more than one phenotype (multiple effects), such as in sickle cell anaemia or starch synthesis in pea seeds.

Polygenic inheritance

Inheritance where traits are controlled by three or more genes, such as human skin colour or height.

Linkage

The physical association of two or more genes on a chromosome that do not show independent assortment.

Down's syndrome

A chromosomal disorder caused by the trisomy of chromosome $21$, characterized by mental retardation and short stature.

Klinefelter's syndrome

A genetic condition in males ($44\text{A} + \text{XXY}$) resulting in sterile individuals with overall masculine development and feminine characters like Gynaecomastia.

Turner's syndrome

A genetic condition in females ($44\text{A} + \text{XO}$) resulting in sterile individuals with poorly developed ovaries.

Nucleosome

A structure formed by negatively charged $\text{DNA}$ wrapped around a positively charged histone octamer.

Okazaki fragments

Small stretches of $\text{DNA}$ synthesized discontinuously in the $5' \rightarrow 3'$ direction on the lagging strand during replication.

Transcription

The process of copying genetic information from one strand of $\text{DNA}$ into $\text{RNA}$.

Splicing

The process in eukaryotes where non-functional introns are removed from $hnRNA$ and functional exons are joined together.

VNTR

Variable Number of Tandem Repeats; a satellite $\text{DNA}$ used as a probe in $\text{DNA}$ fingerprinting.

Homologous organs

Organs having fundamental similarity in structure and origin but different functions, representing divergent evolution.

Analogous organs

Organs having similar functions but different structures and origins, resulting from convergent evolution.

Adaptive radiation

The process of evolution of different species in a given geographical area starting from a point and radiating to other habitats.

Saltation

Speciation occurring by a single step, large mutation as proposed by Hugo de Vries.

Genetic drift

A factor affecting Hardy-Weinberg equilibrium where gene flow occurs by chance, causing a change in frequency.

Haemozoin

A toxin released when parasite-infected $\text{RBCs}$ rupture, responsible for the chill and high fever associated with malaria.

Interferons

Glycoproteins produced by body cells in response to a viral infection, acting as cytokine barriers.

Metastasis

The property of malignant tumor cells to separate and move to distant sites through the blood to invade other tissues.

Statins

Bioactive molecules produced by the yeast Monascus purpureus used as blood cholesterol lowering agents.

Cyclosporin A

A bioactive molecule produced by the fungus Trichoderma polysporum used as an immunosuppressive agent.

BOD

Bio Chemical Oxygen Demand; used as a measure to determine the polluting potential of sewage.

The Evil Quartet

The four major causes of biodiversity loss: Habitat loss and fragmentation, Overexploitation, Invasion of alien species, and Co-extinction.