Paper 2- Biology

• Homeostasis is the term given to an organism's ability to regulate internal conditions even when external conditions change
• Our bodies work hard to regulate blood glucose concentration, temperature, and water levels
• The nervous system consists of the CNS (central nervous system) - the brain and spinal cord, and the PNS (peripheral nervous system) - the nerves that go through the rest of the body
• A reflex is when the signal bypasses the brain and goes straight through the spine to the effector, known as a reflex arc
• Glands can also be effectors which produce specific chemicals your body needs depending on the situation
• The endocrine system is a system of glands that produce or secrete hormones that travel to effectors via the blood
• The pituitary gland in your brain can be considered the main or Master gland as it produces hormones in response to stimuli that travel to other glands in your body
• The pancreas is involved in making sure that your blood glucose levels aren't too high or too low
• Type 1 diabetes is when your pancreas can't produce enough insulin and you have to take insulin injections
• Type 2 diabetes is when your cells no longer absorb the glucose as they should
• Water and nitrogen balance are triple only
• Reproduction: Menstruation occurs in females after puberty
• FSH (follicle stimulating hormone) causes the neck to mature in the ovary
• Progesterone is also produced by the ovaries which maintains the uterus lining
• Contraception options include pills, injections, implants, condoms, diaphragms, IUDs, and clamping the oviduct
• IVF (in vitro fertilization) is a method for couples facing infertility
• Adrenaline increases heart and breathing rate in stressful situations
• Thyroxine controls metabolic rate
• Plants have their own hormones which we can utilize when growing
• Differellins cause seed germination to occur and promote flowering and fruit size
• Ethene induces ripening of fruits
• Auxins control shoot and root growth
• Inheritance: Meiosis is the process by which gametes are produced
• Variation occurs through meiosis and the swapping of genes between chromosomes
• Sexual reproduction leads to variation which can result in organisms becoming better suited to their environment
• Asexual reproduction results in genetically identical offspring, creating a clone of the parent
• Some organisms can reproduce both sexually and asexually
• The genome is the term
• Genome is the term given to all the genetic material in an organism, stored in DNA
• A gene is a section of DNA that codes for a specific protein
• Phenotype is the term given to what code is stored in your DNA specifically, while phenotype is how that code is expressed in your characteristics
• Every three bases in DNA code for an amino acid
• Monomers between the two strands of DNA are called nucleotides, made from a sugar and phosphate group of A, T, C, and G types
• The sequence in DNA is copied by mRNA and taken to a ribosome in the cell where amino acids are connected to make a protein
• Harmful mutations can change a gene resulting in a protein that doesn't function properly
• Some DNA doesn't directly code for proteins but influences how other genes are expressed, known as epigenetics
• Characteristics can be controlled by one gene or multiple genes interacting
• Alleles are different types of the same gene, with dominant alleles being expressed over recessive alleles
• Variation in organisms is due to genes inherited from parents and environmental factors
• Bacterial resistance is evidence of Darwinian evolution, where mutations lead to increased resistance to antibiotics