OOGENESIS • Oogenesis (ovogenesis) is the sequence of events by which oogonia are transformed into mature oocytes • This maturation process begins before birth and is completed after puberty • Oogenesis continues to menopause‚ which is permanent cessation of the menses (bleeding associated with the menstrual cycles) 2 maturation processes of oocytes are involved; Prenatal maturation Postnatal maturation Prenatal Maturation of Oocytes • Primordial germ cells (46‚ 2N) migrate from the wall of
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development and maturing of sex cells through meiotic division. This is a situation whereby two diploid precursors undergo cell division and differentiation to form mature haploid gametes. There are two forms of gametogenesis‚ spermatogenesis (male)‚ and oogenesis (female). “Meiosis and gametogenesis are critical processes in the transmission of genetic material to subsequent generations during sexual reproduction”(Frederic 8346). In other words‚ gametogenesis is the production of sperm and eggs‚ through the
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P1: Explain how sperm and ova are formed by producing an annotated diagram of meiosis and discussing what happens in ogenesis and spermatogenesis In the male‚ meiosis precedes sex cell differentiation. A single spermatogonium enters the first meiotic division as a primary spermatocyte. This division produces two secondary spermatocytes‚ each of which divides to form two haploid spermatids. Each spermatid then differentiates (by a process called spermiogenesis) into a spermatozoon by the elaboration
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Test 3 Chapter 51: 1‚ 2‚ 5‚ 7 1. Most of the metabolic energy needed by a bird for a long-distance migratory flight is stored as a. glycogen. b. fat. c. protein. d. carbohydrates. e. ATP. 2. Which statement about essential amino acids is true? a. They are not found in vegetarian diets. b. They are stored by the body until they are needed. c. Without them‚ one is undernourished. d. All animals require the same ones. e. Humans can acquire all of theirs by eating milk‚ eggs‚ and meat
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-invest reproductive energy differently b. Where and when does fertilization occur in humans? Oviduct/fallopian tube‚ ovulation 400-1. In vertebrate animals‚ spermatogenesis and oogenesis differ‚ in that A) oogenesis begins at the onset of sexual maturity‚ whereas spermatogenesis happens in embryonic development. B) oogenesis produces four haploid cells‚ whereas spermatogenesis produces only one functional spermatozoon. C)
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Genetics Review DNA (Deoxyribonucleic Acid): Stored inside chromosomes and contain all instructions for life It is made up of Ribose (sugar)‚ phosphate‚ and when of 4 Nitrogenous bases (Adenine‚ Thymine‚ Guanine and Cytosine) A Nucleotide consists of a Phosphate molecule‚ a sugar molecule‚ and a Nitrogenous base pair The nitrogenous bases always pair up AT and CG Each human has 46 chromosomes 23 pairs in total 1 pair sex chromosomes (that define your sex‚ male XX‚ female XY) 22
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Human Biology Stage 2B Revision – Test 1 Chapter 10 – Production of Gametes Gonads: Are the primary sex organs Secondary sex organs: Everything else‚ e.g. Seminal Vesicles Males Spermatozoa (sperm): Male gametes Scrotum: Single pouch of skin‚ divided into two sacs internally Lobules: Compartments filled with fine tubes called seminiferous tubules Seminiferous tubules: Fine tubes lined with cells that produce the male gametes. They eventually join together to form a short straight tubule
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Reproduction Male sperm fuses with female egg. If tdf (a gene) is present‚ then the embryo develops testes and produces testosterone. Female Reproductive system • Female baby develops if tdf is not present. • Tdf – a gene located on Y chromosome; if girl‚ then two X chromosomes‚ hence no Tdf. • Female hormones: progesterone and estrogen ( both secreted by mother’s ovaries and placenta which allow female genetilia to develop. Parts of the female reproductive system:
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Mitosis & Meiosis/ Human Development The Cell Cycle Stages of the Cell Cycle: G1 – cell growth S – DNA replication and continued cell growth G2 – Final preparations for division and continued cell growth M – Mitosis or cellular replication Some Important Terms for Replication: Chromosome – rod-shaped body in the nucleus that is only visible during replication that contains DNA and is our hereditary unit. Nucleolus – organelle inside the nucleus composed of RNA for ribosome formation.
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CHAPTER 43 1) 1. C 7. B 2. B 8. A 3. A 9. B 4. B 10. C 5. C 11. B 6. A 12. B 2) Describe the process of synapsis The pairing of homologous chromosomes (23 tetrads become attached to spindle fibers & begin to align on the equator. 3) How does crossover introduce variability in the daughter cells? The homologues separate from one another‚ breaking & exchanging parts- where crossovers occur 4) Define homologous chromosomes Egg & sperm chromosomes that carry genes for the
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