Science reviewer 1

• Ovary


  Produces egg cells
• Fallopian Tube


  Serves as passageway of eggs from the ovary to the uterus
• Uterus


  Serves as site of egg implantation
• Cervix


  Facilitates the passage of sperm into the uterine cavity
• Vagina


  Receives the penis of male during mating
• Hormones play an important role in both male and female reproductive systems to function properly
• Hormones are responsible for sexual development, maturation, and control menstrual cycle of females
• Hormones are responsible for some changes in the body including physical and emotional development
• Hypothalamus


  Although it is very small, it serves a crucial role and function in maintaining body's homeostasis
• Hypothalamus


  Communicates with pituitary gland through nerve impulses and hormone, for this we have the gonadotrophin-releasing hormone, GnRH
• GnRH


  Produced from the cells in the hypothalamus, it triggers the anterior pituitary to release of LH and FSH
• Anterior pituitary


  Part of the pituitary gland that secretes hormones for the gonads
• Estrogen


  Causes the maturation of the female physique with the help of other hormones
• Progesterone


  Prepares the uterus for pregnancy by thickening the uterine lining
• Inhibin


  Inhibits the secretion of FSH and LH to maintains balance in the production
• Menstruation or menstrual cycle


  The monthly flow of blood from the the uterus
• Menstrual phase


  Starts and lasts for an average of 3-7 days, the unfertilized egg cell and the uterine lining that was not used will be shed from the vagina
• Follicular Phase


  Overlaps with the menstrual phase until ovulation, lasts an average of 14-16 days
• Ovulation phase


  Usually occurs around day 12 to 14 in the menstrual cycle
• Luteal phase


  Lasts an average of 14 days, when the follicle releases the matured egg, the follicle will become a corpus luteum
• Positive feedback


  Rising levels of hormones feedback to increase hormone production
• Negative feedback


  Rising levels of hormones feedback to the hypothalamus and pituitary gland to decrease the production of the hormones
• Endocrine System


  Composed of different glands which secrete hormones that regulate metabolism, growth and development, mood, and reproduction
• Nervous System


  Connects all your body parts and transmits signals from one part to another, it is a system of cells, tissues, and organs that regulates the body's responses to internal and external stimuli
• Homeostasis


  The state reached when each part of the body functions in equilibrium with other parts, attained through the regulation of the bodily functions by the endocrine and nervous systems
• DNA


  Double-stranded, with adenine-thymine and cytosine-guanine base pairs, mostly in the nucleus, but may also be found in cytoplasm and mitochondria, blueprint of biological guidelines that living organisms must follow to exist and function properly
• RNA


  Single-stranded, with adenine-uracil and cytosine-guanine base pairs, mostly in the cytoplasm, but may also be found in the nucleus, assists in carrying out DNA's blueprint guidelines
• DNA Replication


  1. Unwinding

  2. Base pairing

  3. Joining
• Replication is needed to ensure that all our body cells must carry the same genetic material and that instructions are copied exactly for the next generation
• Transcription


  1. RNA polymerase binds and opens the DNA molecule

  2. RNA polymerase slides along the DNA strand and links free RNA nucleotides

  3. mRNA molecule breaks away as the DNA strands rejoin, the mRNA leaves the nucleus and goes to the cytoplasm
• Genetic material needed to make proteins are from the DNA but it cannot move outside the nucleus
• Protein synthesis


  1. mRNA binds to ribosome

  2. tRNA molecules carrying amino acid approach ribosome

  3. tRNA anticodon pairs with mRNA start codon (AUG)

  4. Ribosome slides along mRNA to next codon

  5. Another tRNA pairs with second codon

  6. Enzyme joins first and second amino acids by forming peptide bond

  7. Process continues until ribosome reaches stop codon (UAA, UAG, UGA)

  8. Polypeptide chain (protein) is released
• Mutation


  Any change in DNA sequence or in chromosomes of living cells
• Types of cells where mutation can occur

  • Reproductive or sex cells
  • Body or somatic cells
• Mutation in sex cells


  • Can be passed on to offspring
• Mutation in somatic cells


  • Can cause cancer in the body
• Causes of mutation


  • Errors in DNA replication during cell division
  • Exposure to mutagens (radioactive substances, x-rays, ultraviolet radiation and certain chemicals)
  • Viral infections and other infectious agents
• Types of mutation


  • Gene Mutation
  • Chromosomal Mutation
• Gene Mutation


  A small scale mutation in which only one gene is affected. Nucleotides or bases may be added, removed, or changed.
• Types of gene mutation

  • Point mutation
  • Frameshift mutation