CHAPTER 2 SEXUAL REPRODUCTION IN FLOWERING PLANTS 2.1 2.2 2.3 2.4 2.5 Flower – A Fascinating Organ of Angiosperms Pre-fertilisation : Structures and Events Double Fertilisation Post-fertilisation: Structures and Events Apomixis and Polyembryony Are we not lucky that plants reproduce sexually? The myriads of flowers that we enjoy gazing at‚ the scents and the perfumes that we swoon over‚ the rich colours that attract us‚ are all there as an aid to sexual reproduction. Flowers do not exist only
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of the uterus into the fallopian tubes. In the fallopian tubes‚ the egg became fertilized. The one sperm goes directly into the egg and gives genetic material. The egg rejects any other sperm and is now identified as a zygote. Throughout the next few days the single cell zygote divides several times to form a ball of cells called a morula. The cellular division continues and a small cavity is formed between the cells. At this point there is no growth in the embryo’s size the divisions create smaller
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Which of these would be a valid hypothesis? Select one: a. Humans are controlled by forces beyond our understanding. b. Humans and bacteria share a common genetic code. c. Humans should help in the conservation of other animal species. d. Humans are responsible for the sustainable use of resources. e. Human history is determined by a series of supernatural events. Feedback Your answer is correct. Question 2 Incorrect Mark 0.00 out of 2.00 Flag question Question text A hypothesis
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Archasea Bacteria Luca Last Universal Common Ancestor Lucas Characheristics deduce form shared characteristics of A + B today: DNA (cf. RNA) genome No nuclear membrane or intracellular organelles Electron Transport Chains (ETC)- ATP (energy) Proteins Same genetic code Prokaryontes 2.75 bya‚ are responsible for a dramatic increase in atmospheric O2. Cyanobacteria = photosynthesizing bacteria + related prokaryontes Evidence of O2 increase: Rust in rock
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Mitosis and Meiosis Purpose To understand the cell cycle and mitosis and how these two processes function within an organism. To understand meiosis and how this process produces gametes. Mitosis All cells in your body complete a cell cycle in which they grow‚ divide and‚ eventually‚ die. The cell cycle consists of four phases: G1‚ S‚ G2‚ and M (Figure 1). Each phase is associated with a specific cellular function: typically growth‚ synthesis‚ and division. The G1‚ S‚ and G2 phases comprise
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Pregnancy is the fertilization and development of one or more offspring‚ known as an embryo or fetus‚ in a woman’s uterus. It is the common name for gestation in humans. A multiple pregnancy involves more than one embryo or fetus in a single pregnancy‚ such as with twins. Childbirth usually occurs about 38 weeks after conception; in women who have a menstrual cycle length of four weeks‚ this is approximately 40 weeks from the start of the last normal menstrual period (LNMP). Human pregnancy is the
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they are homozygous and when they are different they are heterozygous. These alleles are expressed physically through what is known as the phenotype. An example of a phenotype of a gene is hair color‚ which may be blond or brown. In humans‚ a zygote starts out with a complete set of genes from its mother and father. The DNA is transcribed or copied into RNA sequences known as mRNA. These mRNA sequences are translated to make proteins. These proteins then dictate which chemical proceses will
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I. INTRODUCTION Hydatidiform Mole (H-mole or Gestational trophoblastic disease) is abnormal proliferation and then degeneration of the trophoblastic villi (Garg & Giuntoli‚ 2007). As the cells degenerate‚ they become filled with fluid and appear as clear fluid-filled‚ grape-sized vesicles. The embryo fails to develop beyond a primitive start. Abnormal trophoblast cells must be identified because they are associated with choriocarcinoma‚ a rapidly metastasizing malignancy. (Pillitteri‚ 2010)
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like motion so it can makes its way to the egg. The sperm penetrates the egg‚ once it penetrates the membrane of the egg hardens so no more can enter‚ the sperm and egg chromosomes (each has 23‚ located in the nucleus) joint together to form a zygote
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Leber’s Hereditary Optic Neuropathy (LHON) is a kind of genetic disorder that caused by the pathogenic variants in mtDNA (mitochondrial DNA) leading to a bilateral visual loss during young adult life‚ especially in males. Mitochondrial DNA is found in mitochondria which breakdowns carbohydrates and fatty acids to generate energy so that the body cells can use. Mitochondrial DNA is inherited maternally‚ it is because the paternal mitochondria in sperm have disappeared during the early embryogenesis
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