Immune System and Nervous System

Immune System and Nervous System

• B-cells produce antibodies.
• Helper T-cells (CD4+ T-cells) assist in activating B-cells and cytotoxic T-cells.
• Plasma T-cells are not a type of T-cell.
• Basophils release histamine during allergic reactions.
• Natural Killer (NK) cells are part of the innate immune system.
• Humoral immunity involves B-cells and the production of antibodies.
• Neutrophils perform phagocytosis.
• Regulatory T-cells regulate and suppress immune responses.
• Eosinophils attack and kill parasitic infections.
• Bone marrow produces leukocytes.
• Antibodies are not a physical barrier of innate immunity.
• Adaptive immunity is specific and creates memory cells.
• Inflammation involves the release of histamine and increased blood flow.
• Fever raises body temperature to inhibit pathogen growth.
• The spinal cord is part of the central nervous system (CNS).
• The nervous system consists of the CNS and the peripheral nervous system.
• The sympathetic nervous system triggers the "fight-or-flight" response.
• The parasympathetic nervous system handles the "rest-and-digest" response.
• The somatic nervous system controls voluntary movements.
• The hypothalamus regulates body functions like temperature and hunger.
• The optic nerve controls vision.
• The oculomotor nerve controls most eye movements.
• The brain and spinal cord form the central nervous system.
• The sensory (afferent) division brings sensory information to the CNS.
• The facial nerve controls facial expressions.
• The vestibulocochlear nerve controls hearing and balance.
• The thalamus relays sensory and motor signals.
• The autonomic nervous system controls involuntary actions like digestion.
• The cerebellum coordinates muscle movements.
• The autonomic nervous system regulates heart rate and breathing.

Feedback Mechanism

• A feedback mechanism is a loop where output influences the input to regulate a system.
• Positive and negative feedback are the two primary types of feedback mechanisms.
• Positive feedback amplifies the initial stimulus.
• Negative feedback maintains stability by counteracting changes.
• Temperature regulation is an example of negative feedback
• Uterine contractions during labor are an example of positive feedback.
• The endocrine system releases hormones to regulate body functions. -The pituitary gland is the "master gland" that controls other glands.
• The thyroid gland regulates metabolism, growth, and development.
• Melatonin regulates the sleep-wake cycle.
• Insulin's main function is to lower blood glucose levels.
• Glucagon is released when blood glucose levels are too low.
• Insulin is produced in the pancreas.
• Glucagon raises blood sugar.
• The liver stores glucose in the form of glycogen.
• Antidiuretic hormone (ADH) regulates water balance by controlling kidney function.
• High blood concentration (dehydration) triggers ADH release.
• ADH increases water reabsorption in the kidneys.
• The hypothalamus detects changes in blood concentration, triggering ADH release.
• Adrenaline is responsible for the "fight-or-flight" response.
• Blood vessels widen during vasodilation.
• Sweating and vasodilation is the body's response to a high temperature.
• Vasoconstriction and shivering is the body's response to a low temperature.
• The adrenal gland releases cortisol during stress.
• Parathyroid hormone is involved in calcium regulation.
• The kidneys filter waste from the blood.
• The adrenal gland sits atop the kidneys.
• Homeostasis maintains a stable internal environment.
• The pituitary gland controls other endocrine glands.
• Erythropoietin increases red blood cell production.

Mendel's Law of Inheritance

• Gregor Mendel is known as the "Father of Genetics."
• Gregor Mendel used pea plants in his experiments.
• The Law of Segregation states that each organism inherits two alleles for each trait, separating during gamete formation.
• The Law of Independent Assortment states that genes for different traits are inherited independently.
• The Law of Dominance states a dominant allele masks the effect of a recessive allele.
• Tall height was dominant in Mendel's pea plant experiments.
• White flower color was a recessive trait in Mendel's pea plant experiments.
• Genotype refers to the genetic makeup of an organism.
• Phenotype refers to the observable characteristics of an organism.
• A heterozygous genotype looks like Aa.
• A homozygous genotype can be AA or aa.
• The expected phenotypic ratio in a monohybrid cross of heterozygous parents (Aa x Aa) is 3:1.
• The phenotypic ratio in a dihybrid cross of heterozygous parents (AaBb x AaBb) is 9:3:3:1.
• An organism homozygous dominant for a trait has two dominant alleles.
• Mendel selectively bred plants with distinct traits.
• The Law of Dominance states that one allele can completely mask another.
• Linked genes violate the Law of Independent Assortment.
• A test cross determines an unknown genotype.
• The F2 generation of monohybrid cross ratio is 3:1.
• The F2 generation of dihybrid cross ratio is 9:3:3:1.
• Ronald Fisher integrated Mendel's genetics with natural selection.
• Incomplete dominance shows a blended trait in a heterozygous individual.
• Codominance occurs when both alleles are equally expressed.
  • Cystic fibrosis is a genetic disorder inherited through Mendelian principles.
• Traits controlled by multiple genes are an example of Polygenic inheritance.
• A monohybrid cross studies one trait.
• A dihybrid cross studies two traits.

Mendel's Laws Revisited

• Gregor Mendel is considered the "Father of Genetics".
• Gregor Mendel used pea plants in his experiments.
• Mendel’s work was initially rejected but gained recognition when it was linked to the Chromosome Theory of Inheritance
• The Law of Segregation mandates each organism inherits two alleles for each trait; these separate during gamete formation.
• Genes for different traits assort independently during gamete formation, in accordance with the Law of Independent Assortment.
• The Law of Dominance suggests dominant alleles mask recessive alleles.
• AA and aa were the parental types used in Mendel’s first cross.
• The phenotypic ratio in the F2 generation of a monohybrid cross is 3:1.
• A test cross determines an unknown genotype.
• A dihybrid cross studies two traits.
• In the F2 generation of a dihybrid cross, the phenotypic ratio is 9:3:3:1.
• A heterozygous genotype appears as Aa.

Additional Genetic Principles

• A homozygous genotype can be AA or aa.
• Genotype is the genetic makeup of an organism.
• Phenotype is the observable characteristics of the organism.
• A heterozygous individual displaying a blended trait is an example of Incomplete dominance.
• Codominance is displayed when both alleles are equally expressed.
• Type AB blood type shows codominance.
• Sickle cell anemia exemplifies a Mendelian disorder.
• Mendelian disorders follow single-gene inheritance.
• Cystic Fibrosis is inherited as an autosomal recessive trait.
• Hemophilia is considered an X-linked recessive genetic disorder.
• Linked genes break the Law of Independent Assortment.
• Mendel’s studies explain how traits are passed from parents to offspring.
• Mendel chose pea plants, as they possess distinct traits and have short life cycles.

Sex Linkage Basics

• Sex linkage is the inheritance of traits via sex chromosomes.
• In humans, biological sex determination relies on X and Y chromosomes.
• The determination system in humans is XX/XY
• E. McClung first identified the X chromosome in grasshoppers.
• The SRY gene on the Y chromosome drives male development in humans.

Sex Determination Systems

• Birds and some reptiles use the ZW sex determination system.
• In the ZW system, females are heterogametic.
• Grasshoppers and cockroaches use the XO sex-determination model.
• High temperatures determine that turtles will be female.
• Being haploid determines that honeybees are male.
• X-linked recessive traits show up more in males since males only have one copy of the X chromosome.
• Hemophilia stands as an X-linked recessive disorder.
• Daughters inherit the affected X chromosome from their father, who has an X-linked recessive disorder.
• Fragile X syndrome is considered an X-linked dominant disorder.
• 50% will be color blind in the male children of a woman caring the color blindness has children with a normal male.
• Male infertility is a Y-linked trait.
• A Barr body is an inactive X chromosome in females.
• Hairy ears provides an example of a Y-linked trait.
• One X chromosome is randomly inactivated in X-inactivation in females.

Sex-Linked Disorders and Associated Traits

• Klinefelter syndrome stems from an extra X chromosome (XXY).
• Turner syndrome results from a missing X chromosome (XO).
• Male-pattern baldness constitutes as a sex-limited trait.
• Baldness is a sex-influenced trait.
• Duchenne muscular dystrophy genetic source is housed the X chromosome.
• Triple X syndrome stems from extra X chromosome in females (XXX).
• Cats, in particular those with calico coloration, show common sex-linked inheritance.
• Duchenne muscular dystrophy is a sex-linked disorder sourced by a mutation to the dystrophin.
• Red-green color blindness is present in the X chromosome.
• X-linked recessive traits are expressed more in males.
• The Y chromosome supports the sex-determination.

Population Evolution: Guiding Principles

• Evolution is the proportions of different genotypes varying in a population over generations.
• A population constitutes the same species individuals interbreeding to produce fertile offspring.
• The total of all alleles within a population represents a gene pool.
• Artificial selection isn’t a source for genetic variation.
• Point mutations are a change a single nucleotide without changing the complete sequence.
• Nonsense mutations are at the protein level.
• Natural selection gives adaptation for evolution.
• Charles Darwin is credited with the theory of natural selection.
• Artificial selection constitutes selection through desirable traits given by people within animals and plants.
• Random mating isn't needed for natural selection.
• Genetic drift is a change through allele frequencies given through accidents.
• The founder effect represents genetic drift when a tiny population colonizes through a new origin.
• The bottleneck effect represents the population drop of drastic size due to catastrophe.
• Gene flow transports alleles in and out given by population.
• Gene flow typically reduces population difference, through genetics.
• Hardy-Weinberg Equilibrium projects through genetic makeup not changing the population. Small population size doesn't mandate the Hardy-Weinberg equilibrium.
• When not through Hardy-Weinberg equilibrium, that population is evolving.
• Crossing over has a great contribute for genetic variation which provides sexual production.
• Independent assortment gives genetic recombination to the offspring.
• Adaptive evolution leads to adaptive evolution consistently.
• Through evolution, mutations primarily create variations in gene code.
• Adaptation offers a bird developing a longer break to get nectar.