reproduction

• Sexual reproduction involves the fusion of gametes from two parents to produce offspring with genetic variation.
• How cells multiply

  Cells multiply in two different ways. Mitosis: one cell creates a clone with 46 chromosomes. Meiosis: cells make a copy of themselves with half the chromosomes
• Asexual reproduction is the type where a new organism is produced from one parent and the offspring is identical to the parent, e.g., bacteria
• Chromosomes


  Threadlike structures made of protein and a single molecule of DNA that serve the genomic information from cell to cell. Found inside the nucleus of a cell. One cell has 46 chromosomes
• Gametes are male sperm and female eggs. Zygote is a fertilized egg cell resulting from the union of a female gamete with a male gamete
• Male reproductive system: testes produce sperm and sex hormones, epididymis stores sperm, vas deferens conducts and stores sperm, seminal vesicle and prostate gland contribute to semen, urethra conducts sperm, bulbourethral gland contributes to semen, penis is for sexual intercourse, scrotum holds and protects testicles
• Sexual intercourse involves the erect penis being inserted into the vagina with fluid secretions from male glands
• Gene


  The basic unit of heredity passed from parent to child. Its function is carrying the hereditary information from one generation to the next. Genes are made up of sequences of DNA and are arranged one after another at specific locations on chromosomes in the nucleus of cells
• DNA aka deoxyribonucleic acid


  The molecule that carries genetic information for the development and functioning of an organism. Made up of two double strands that wind around each other to resemble a twisted ladder known as a double helix. Located in the cell nucleus with a small amount also found in the mitochondria. Genome is inherited half from father and half from mother
• Reproduction

  Organism tries to make a copy of itself or create a new organism. Asexual reproduction involves one parent, no gametes produced, offspring identical to parent. Sexual reproduction involves two organisms, gametes produced, offspring show genetic variation
• Sexual reproduction is the production of a new organism by the combination of genetic information from two individuals of different sexes
• Human gametes are sex cells. Male sex cell is sperm with genetic information in the head and tail for propulsion. Female sex cell is egg (ovum)
• Female reproductive system: ovary produces eggs and hormones, oviducts transport eggs, uterus receives penis during intercourse, clitoris contributes to sexual arousal, breasts produce milk, fallopian tubes transport eggs from ovary to uterus
• Chromosomes

  Threadlike structures made of protein and DNA, carrying genomic information from cell to cell, found inside the nucleus of a cell, one cell has 46 chromosomes
• Fertilisation and implantation


  Sperm penetrates and fertilises egg preventing other sperm from entering, sperm and egg each have 23 chromosomes which together make 46, fertilisation results in a zygote, zygote attaches to uterine lining known as implantation
• Reproduction

  • Asexual reproduction involves one parent, offspring are genetically identical to the parent, cell division is only mitotic
  • Sexual reproduction involves two organisms, offspring show genetic variation, gametes are produced by meiotic division and zygote develops by mitotic division
• If the egg is not fertilised or a fertilised egg does not implant, the lining of the uterus is shed during the menstrual period and the process repeats
• Asexual reproduction is the type of reproduction in which a new organism is produced from one parent and the offspring is identical to the parent
• During ovulation, the hormone progesterone is made by the ovaries to prepare the uterus for pregnancy
• Sexual intercourse

  Erect penis inserted into vagina, fluid secreted by male gland serves as lubricant, rhythmical movement leads to ejaculation, semen expelled into vagina, feelings experienced during ejaculation are known as orgasm
• Cells multiply in two different ways: mitosis and meiosis
• Gene

  The basic unit of heredity passed from parent to child, carrying hereditary information from one generation to the next, made up of sequences of DNA arranged on chromosomes
• DNA


  Molecule carrying genetic information for the development and functioning of an organism, made up of two double strands of DNA forming a double helix, located in the cell nucleus
• Meiosis is a type of cell division that reduces chromosome number by half and results in four daughter cells containing one copy of each chromosome.
• Chromosome pairing and independent assortment ensure genetic diversity between gametes during meiosis.
• The process of sexual reproduction includes the production of haploid gametes through meiosis, followed by their union during fertilization to form diploid zygotes.
• Meiosis is a specialized process of cell division resulting in four sex cells or gametes with half the number of chromosomes as the original cell.
• Testosterone is secreted by Leydig's cells in the interstitial tissue between the seminiferous tubules.
• Sperm cells are produced by spermatogenesis in the seminiferous tubules within the testes.
• Asexual reproduction is when an organism produces genetically identical offspring without fertilization, such as budding or fragmentation.
• Zygote


  Fertilized egg cell that results from the union of a female gamete (egg or ovum) with a male gamete (sperm)
• Male sex cell (sperm)


  • Head: the chromosomes (23) (genetic information) are tightly packed in the nucleus
  • Tail: lashes from side to side and propels the sperm forwards
• What type of cell division is happening in the fallopian tube? Mitosis
• Female reproductive system

  • Ovary - produces eggs and the hormones oestrogen and progesterone
  • Oviducts - transport ovulated egg (or embryo if fertilization occurred) from ovary to uterus
  • Uterus - receives penis during intercourse; serves as birth canal
  • Clitoris - contributes to sexual arousal
  • Breasts - produce milk
  • Fallopian tubes aka oviducts, uterine tubes - are the females structures that transport the egg from the ovary to the uterus each month
• Asexual reproduction is the type of reproduction in which a new organism is produced from one parent and the offspring is identical to the parent. Not humans e.g. bacteria
• Fertilization and implantation


  The process of fertilization occurs when a sperm penetrates and fertilizes an egg (via fallopian tubes), preventing other sperm from entering the egg. Sperm and egg have 23 chromosomes together, making 46. If the sperm has an X chromosome and it came into contact with an egg that has an X chromosome, a female is produced. However, if the sperm that has a Y chromosome came into contact with an egg that has an X chromosome, you would get an XY chromosome which forms a male. Fertilization is when the sperm fuses with an egg and you get a zygote which happens in the fallopian tube. The zygote remains there for 3 to 4 days and begins to multiply as it continues its journey towards the uterus. The zygote undergoes further cell division. Upon reaching the uterus, the zygote attaches itself to the uterine lining known as implantation
• Male reproductive system

  • testes - produces sperm and sex hormones
  • Epididymis - duct where sperm mature and stored
  • Vas deferens - conducts and also stores sperm
  • Seminal vesicle - contributes nutrients and fluid to semen
  • Prostate gland - contributes basic fluid to semen
  • Urethra - conducts sperm
  • Bulbourethral gland - contributes mucoid to semen
  • Penis - organ of sexual intercourse
  • Scrotum - the bag of skin that holds and helps to protect the testicles
• Meiosis

  Gametes are produced by meiotic division and zygote develops by mitotic division
• Sexual intercourse

  When the erect penis is inserted into the vagina, drops of fluid secreted by the male gland emerge from the tip of the penis and serve as a lubricant as does the mucus lining of the vagina. Rhythmical movement of the penis eventually results in ejaculation - semen is forcibly expelled from the penis into the vagina. The feelings experienced during ejaculations are known as orgasm
• Genes are the basic unit of heredity passed from parent to child. Their function is carrying the hereditary information from one generation to the next. Genes are made up of sequences of DNA and are arranged one after another at specific locations