AQA Biology Paper 2 ALL SOLUTION LATEST EDITION 2023 GUARANTEED GRADE A+

homeostasis A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level nervous system A conglomeration of billions of cells specifically designed to provide a communication network within the human body. receptors Special structures that allow living organisms to sense the conditions of their internal or external environment stimuli Changes, occurring within or outside the body, that affect nervous system functioning. coordination centres receive and process info from receptors effectors muscles or glands that carry out the correct response to stimuli nerve A cordlike bundle of neuronal axons and/or dendrites and associated connective tissue coursing together outside the central nervous system central nervous system The brain and spinal cord; CNS sensory neurones nerve cells that carry messages from cells in the sense organs to the CNS motor neurones Nerve cells that carry messages from the CNS to effectors gland An organ that produces and releases chemicals either through ducts or into the bloodstream. reflex A simple, automatic response to a sensory stimulus, such as the knee-jerk response. Automatic and rapid; they do not involve the conscious part of the brain. reflex arc nerve pathway in which an impulse crosses only two synapses before producing a response; stimulus - receptor - sensory neurone - relay neurone - motor neurone - effector - response neurotransmitters Chemical messengers that cross the synaptic gaps between neurons. relay neurones Nerve cells that carry signals from sensory neurones to motor neurones cerebral cortex The part of the brain where information processing takes place. Divided into four lobes. medulla The base of the brainstem; controls heartbeat and breathing. hypothalamus A neural structure lying below the thalamus; it directs several maintenance activities (eating, drinking, body temperature), helps govern the endocrine system via the pituitary gland, and is linked to emotion and reward. pituitary gland The endocrine system's most influential gland. Under the influence of the hypothalamus, it regulates growth and controls other endocrine glands. cerebellum A large structure of the hindbrain that controls fine motor skills. accommodation The process by which the eye's lens changes shape to focus near or far objects on the retina. iris A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening. pupil The adjustable opening in the center of the eye through which light enters. cornea Clear membrane at the front of the globe covering the iris, pupil, and anterior chamber. Responsible for 60% of the eye's focusing power. lens The transparent structure behind the pupil that changes shape to help focus images on the retina. retina The light-sensitive inner surface of the eye, containing the receptor rods and cones plus layers of neurons that begin the processing of visual information. sclera Dense fibrous opaque outer coat enclosing the eyeball except the part covered by the cornea; The "white" of the eye ciliary muscle muscle that alters the shape of lens to accommodate vision suspensory ligament A series of fibres that hold the lens of the eye in place optic nerve the nerve that carries neural impulses from the eye to the brain circular muscles Muscles found in the iris that contract in bright light and relax in dim light radial muscles Muscles found in the iris that relax in bright light and contract in dim light hyperopia A condition in which visual images come to a focus behind the retina of the eye and vision is better for distant than for near objects -- called also farsightedness. myopia A condition in which the visual images come to a focus in front of the retina of the eye because of defects in the refractive media of the eye or of abnormal length of the eyeball resulting especially in defective vision of distant objects -- called also nearsightedness. convex curving outward b11 ... hormone Chemical messengers that are manufactured by the endocrine glands, travel through the bloodstream, and affect other tissues endocrine system Glands that secrete hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells. ADH Antidiuretic hormone; controls water levels in the blood, causes more water to be reabsorbed by the kidneys FSH Follicle stimulating hormone; In females, FSH stimulates the ovaries to develop eggs and secrete oestrogen; in males, FSH stimulates spermatogenesis. oogenesis The production of mature egg cells. oestrogen Female sex hormone which stimulates the lining of the womb to build up in preparation for a pregnancy. ovaries Female organs that produce the egg cells and hormones adrenaline A hormone released into the bloodstream in response to physical or mental stress; produces "fight or flight" response insulin A protein hormone synthesized in the pancreas that regulates blood sugar levels by facilitating the conversion of glucose to glycogen. thyroid gland endocrine gland located below the voice box; it produces hormones which control metabolism adrenal gland a pair of endocrine glands that sit just above the kidneys and secrete hormones that help arouse the body in times of stress. testes Male sex glands or gonads that produce the male sex cells glucagon A protein hormone secreted by pancreatic endocrine cells that raises blood glucose levels; an antagonistic hormone to insulin. type 1 diabetes Diabetes of a form that usually develops during childhood or adolescence and is characterized by a severe deficiency of insulin, leading to high blood glucose levels. type 2 diabetes Diabetes of a form that develops especially in adults and most often obese individuals and that is characterized by high blood glucose resulting from impaired insulin utilisation coupled with the body's inability to compensate with increased insulin production. thyroxine Also called thyroid hormone, produced and secreted by follicle cells in the thyroid gland. It targets all cells in the body and increases overall body metabolism. negative feedback A primary mechanism of homeostasis, whereby a change in a physiological variable that is being monitored triggers a response that counteracts the initial fluctuation. fallopian tube Tubes which carry eggs from the ovaries to the uterus and which provides the place where fertilization occurs. cervix The opening to the uterus uterus A hollow muscular organ in the pelvic cavity of the female, in which the embryo is nourished and develops before birth prostate gland a gland surrounding the neck of the bladder in male mammals and releasing a fluid component of semen. seminal vesicle each of a pair of glands which open into the vas deferens near to its junction with the urethra and secrete many of the components of semen. sperm duct Tube that carries sperm from the testes to the urethra. urethra Duct through which urine is discharged. scrotum External sac that contains the testes ovulation The process of releasing a mature egg (ovum) into the fallopian tube each month menstrual cycle Cycle during which an egg develops and is released from an ovary and the uterus is prepared to receive a fertilized egg. LH Luteinising hormone; triggers ovulation testosterone A male sex hormone produced by the testes; women secrete smaller amounts from the adrenal cortex and ovary; triggers the development of male secondary sexual characteristics menopause The time of natural cessation of menstruation; also refers to the biological changes a woman experiences as her ability to reproduce declines. progesterone inhibits further Luteinizing Hormone (LH) production, which stops ovulation. contraception Any method of preventing conception (the union of the male sperm and the female ovum). spermicide a chemical that kills sperm, available as a contraceptive in a variety of forms, such as foams, creams, and suppositories vasectomy removal of a segment of the vas deferens to produce sterility in the male in vitro fertilisation IVF. Eggs are collected from the woman after hormonal stimulation. Sperm is collected and added and viable embryos are placed into the woman's uterus. phototropism Plant growth in response to light gravitropism response of a plant to the force of gravity auxins Plant hormones that lead to phototropism by elongating the dark side of the plant, and to gravitropism by inhibiting growth on the underside of the roots. Stimulate growth in shoots, inhibit growth in roots. gibberellins A class of related plant hormones that stimulate growth in the stem and leaves, trigger the germination of seeds and breaking of bud dormancy, and stimulate fruit development. herbicide A substance used to destroy plants, especially weeds ethene A gaseous plant hormone that enhances fruit ripening. b12 ... thermoregulatory centre Region of the hypothalamus that monitors and regulates body temperature. vasodilation A widening of the diameter of a blood vessel; increase the rate of heat transfer. vasoconstriction Reduces blood flow and heat transfer by decreasing the diameter of superficial blood vessels. erector muscle Small muscles in the dermis that pull hairs upright in response to low body temperature. Causes goose bumps. sweat gland secrete a mixture of water, dissolved salts, and urea via sweat pores sebaceous gland Any of the small sacculated glands lodged in the substance of the derma, usually opening into the hair follicles, and secreting an oily or greasy material composed in great part of fat which softens and lubricates the hair and skin. kidneys Filter waste from the blood like urea, water, salt and proteins. selective reabsorption The absorption of certain selected molecules back into the blood from the fluid in the nephron tubule renal artery blood vessel that carries blood to the kidney spores a minute, typically one-celled, reproductive unit capable of giving rise to a new individual without sexual fusion, characteristic of lower plants, fungi, and protozoans. renal vein blood vessel that carries blood away from the kidney and toward the heart bladder Stores urine parthenogenesis type of asexual reproduction in which a new individual develops from an unfertilized egg dialysis a procedure to remove waste products from the blood of patients whose kidneys no longer function genome All the genetic information in an organism; all of an organism's chromosomes. kidney transplant replacement of a diseased kidney with one that is supplied by a compatible donor (usually a family member or a cadaver who has donated the kidney prior to death) double helix The form of native DNA, referring to its two adjacent polynucleotide strands wound into a spiral shape. base pairs Any of the pairs formed between complimentary bases in the two nucleotide chains of DNA, such as A-T and C-G (DNA); A-U and C-G (RNA) immunosuppressant drug A drug that suppress the immune system of the recipient of a transplanted organ to prevent rejection mitochondrial DNA A small amount of DNA that is located in the mitochondria of cells. Inherited only through the mother. b13 ... asexual reproduction A reproductive process that involves only one parent and produces offspring that are identical to the parent. nucleotide A building block of DNA, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group. transcription the organic process whereby the DNA sequence in a gene is copied into mRNA sexual reproduction A reproductive process that involves two parents that combine their genetic material to produce a new organism, which differs from both parents translation the process whereby genetic information coded in messenger RNA directs the formation of a specific protein at a ribosome in the cytoplasm meiosis A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores. mRNA A type of RNA, synthesized from DNA, that attaches to ribosomes in the cytoplasm and specifies the primary structure of a protein. gamete A haploid cell such as an egg or sperm. Unite during sexual reproduction to produce a diploid zygote. diploid an organism or cell having two sets of chromosomes or twice the haploid number; 2n; in humans, 46 tRNA An RNA molecule that functions as an interpreter between nucleic acid and protein language by picking up specific amino acids and recognizing the appropriate codons in the mRNA codon A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid haploid an organism or cell having only one complete set of chromosomes; n; in humans, 23 autosomes Any chromosome that is not a sex chromosome protein synthesis The process in which amino acids are arranged in a linear sequence through the processes of transcription of DNA and to RNA and the translation of RNA to a polypeptide chain. pollen A fine dust that contains the sperm of seed-producing plants CONTINUED..