Biology

• The nucleus is the control centre of the cell, containing genetic material (DNA) that controls all activities within the cell.
• Ribosome - The site of protein synthesis
• Mitochondria - Site of aerobic respiration
• Vacuole - Contains water and waste products
• Chloroplast - Site of photosynthesis
• Cell membrane - Controls what enters/leaves the cell
• Double circulatory system is where blood passes through the heart twice before returning to the body
• Pacemaker is found in the wall of right atrium
• Arteries have thicker walls due to high blood pressure
• Veins have small walls and a large lumen to allow blood to flow through easily.
• Capillaries are only one cell thick and have a very thin wall to allow for exchange of materials easily.
• Meiosis is the process of cell division that produces four haploid gametes
• Mitosis is a type of cell division that results in two daughter cells each identical to the parent cell.
• Two reasons why sexual reproductuon causes variation offspring is because gametes are not genetically identical and you get genetic information from both parents.
• the two hormones given to woman during ivf are follicle stimulating hormone (FSH) and luteinising hormone (LH)
• hormones given during ivf treatment interact together to prepare the body for pregnancy progesterone and oestrogen thickening the lining of the uterus preparing for implantation.
• One factor that can affect the probabilty of a woman having a child as a result of ivf is the age of the woman
• the advantages of sexual reproduction are that it produces genetic variation and allows for the production of offspring with different combinations of genes
• The advantages of asexual reproduction are

  only one parent needs

  more time and energy efficient

  many identical offspring’s can be produced
• The disadvantages of asexual reproduction are that there is no genetic variation and are all prone to the same disease.
• The disadvantages of sexual reproduction are that time and energy are needed to find a mate and it takes longer than asexual reproduction.
• DNA is a polymer of nucleotides made up of two strands forming a double helix.
• A gene is a small section of dna
• Each gene codes for a particular sequence of Amina acids.
• Sexual reproduction in animals requires a sperm and egg cell
• Sexual reproduction in plants requires pollen and egg cells in flowering plants
• the Process of meiosis is

  copies of genetic information are made

  cell divides to form four gametes each with a single set of chromo

  all gametes are genetically different to each other

  gametes join in fertilisation to restore the normal number of chromosomes
• Dan contains four bases A, G , C , T
• Bases a and t are complimentary and bases g and c are complimentary
• The order of bases controls the order of amino acids
• There are environmental and genetic factors to your appearance
• Some genetic factors are eye colour And origional hair colour.
• A gamete is a haploid cell that contains half the number of chromosomes of a normal cell
• A chromosome is a long, coiled DNA molecule that carries genetic information.
• A gene is a section of DNA that codes for a specific protein.
• An allele is a different version of a gene that codes for a different amino acid.
• A dominant allele is an allele that is always expressed and is dominant over the recessive allele
• A recessive allele is an allele that is masked by another allele.
• homozygous means having two identical alleles for a particular gene or genes
• Heterozygous means having two different alleles for a particular gene.