Yr10 Semester 1 Biology

• Asexual reproduction


  • Only one parent is needed
  • Offspring are clones
  • Pros: Energy efficient, lots of offspring very quickly
  • Cons: Clones are more susceptible to extinction due to environmental factors
  • Common in smaller less complex organisms
• Sexual reproduction


  • Two parents needed
  • Offspring are genetically diverse
  • Pros: offspring are genetically diverse and not as susceptible to extinction
  • Cons: Not energy efficient, less offspring over a longer period of time
  • Common in larger more complex organisms
• Types of Asexual Reproduction


  • binary fission
  • Fragmentation
  • Vegetative propagation
  • Budding
  • Spores
• Male reproductive system structures


  • testes
  • epididymes
  • vas deferens
  • urethra
  • prostate
  • penis
• Testes


  Found in scrotum. Sperm is produced in seminiferous tubes in the testes. 1500 seconds/ sec
• Epididymis


  Take sperm out of testes into vas deferens. Sperm mature and learn how to swim in epididymis
• Vas deferens


  Tubes that loop up and then down. Sperm travel through here during ejaculation
• Urethra


  Tube that runs through the penis. Transports sperm and urine
• Prostate


  Large gland found just under bladder. Produces seminal fluid
• Penis


  Is part of both the urinary and reproductive system so it can transport both urine and semen
• Seminal Fluid


  an alkaline, sugar-rich fluid
• Sperm


  The male gamete, when added to seminal fluid it is called semen
• Female reproductive system structures


  • ovaries
  • fallopian tubes
  • uterus
  • cervix
  • endometrium
  • vagina
• Ovaries


  Eggs (ovum) are produced here
• Fallopian tubes


  Sometimes called the oviduct. Is the tube that takes the ovum to the uterus
• Uterus


  Where fertilization occurs if there are sperm cells present. Sometimes fertilization can occur in the top third of the oviduct. IF fertilized the zygote becomes an embryo and then implants itself in the uterine wall
• Endometrium


  The uterine wall is called the endometrium. This is where the embryo gets implanted. This is bloody and nutrient-rich and is what is shed during menstruation
• Cervix


  canal leading into the uterus. Many sperm are killed here as it has measures to keep it clean which also leads to it killing sperm
• Vagina


  Entrance to the cervix and the female reproductive system. The vagina extends from the base of the uterus (called the cervix) to the female external genitals (called the vulva). The vulva consists of three major structures: the clitoris, labia minora and labia majora
• Ovum


  The female gamete, sometimes called the egg
• Gamete


  Sex cells
• Gonad


  The organs that produce gametes. In male humans it's the testes, in females it's the ovaries
• Menstruation


  Occurs at the start of the menstrual cycle and usually lasts for about 5 days. Menstruation is a process where the lining of the uterus (the endometrium) is shed and flows out through the vagina
• Ovulation


  Occurs in the middle of the cycle and is the process where an ovum (egg) is shed from an ovary. Usually, one egg is released each month from one of the ovaries. Unless the egg is fertilised by a sperm, it travels down through the oviduct into the uterus and passes out through the vagina
• Fertilisation


  The union of gametes
• Zygote


  One single fertilised cell
• Embryo


  What is formed when a zygote undergoes mitosis to grow into an embryo
• FSH


  increases follicle development (ovum maturation) in the ovaries. Its levels are relatively high at the start of the menstrual cycle
• LH


  triggers ovulation (egg release from a follicle). Its levels peak in the middle of the menstrual cycle
• Oestrogen


  repairs and thickens the uterine lining. It is made by follicles and its levels increase from the beginning of the cycle and peak just before ovulation, after which its levels drop off
• Progesterone


  maintains the uterine lining (for the nourishment of the developing embryo). It is secreted in large quantities after ovulation by a ruptured follicle (called a corpus luteum). If there is no implantation of an embryo (no pregnancy), progesterone levels drop which triggers menstruation
• Karyogram


  images of someone's full set of chromosomes. Sometimes called a karyotype. Can identify sex or reveal chromosomal mutations
• Chromosomes (maternal, paternal and homologous)


  • packages made of DNA wrapped around histones. 23 pairs total in every body cell except sex cells
  • Maternal: the chromosome from a pair that is from the mother
  • Paternal: the chromosome in a pair that is from the father
  • Homologous: Pairs of chromosomes that are the same numbering
• Autosomes


  One of two types of chromosomes. The regular type, not sex. Pairs 1-22 are all autosomal pairs
• Sex chromosomes


  The XY chromosomes, XY for males and XX for females. Pair 23
• Diploid

  All normal body cells. Contain 46 chromosomes or 23 pairs
• Haploid

  Sex cells. No pairs just 23 chromosomes
• Genes


  Genes are regions of DNA along a chromosome that code for specific traits (the production of specific proteins). On each chromosome, there are anywhere between 80 and 2000. The sequence of bases varies from one gene to another
• Alleles


  New types of genes formed from mutations
• Both males and females have two sex chromosomes. In females, it is two Xs; in males, it is an X and a Y. There are some mutations where there may be more, but they are rare and abnormal. A maternal diploid cell will always give the child an X as the mother only has X to give. The paternal diploid cell has a 50 50% chance of giving X or Y. Because of this, there is a 50% chance of each sex