169 Questions
What is the primary function of the nucleolus within the cell nucleus?
To direct the synthesis of a specific protein
Which step of DNA replication involves the breaking of hydrogen bonds between base pairs?
Breaking the hydrogen bond between base pairs
Which protein is responsible for giving DNA its coiling shape and helping control gene activity?
Histone protein
What happens to particular sections of DNA when it's time for transcription?
They are unpacked
What is the role of DNA polymerase during DNA replication?
Adds the correct nucleotides to the free end of the new strand
Which nitrogen base is not found in DNA?
Uracil
What is the primary mechanism by which DNA ligase maintains the integrity of genetic code?
By repairing breaks in the DNA strand
Which process ensures that the final mRNA contains only the necessary genetic information before leaving the nucleus?
RNA splicing
Which type of mutation can alter the entire reading frame of the DNA sequence?
Frameshift mutation
What is the primary difference between missense and nonsense mutations?
Missense mutations alter a single amino acid, while nonsense mutations produce a stop codon
What is the primary mechanism by which the redundancy of the genetic code guards against mutations?
By increasing the number of codons for each amino acid
Which process is primarily responsible for the selective expression of genes during cell differentiation?
Transcription
What is the primary cause of Turner syndrome?
Translocation
What is the outcome of crossing over in meiosis?
Increase in genetic variability
What is the most common cause of Down syndrome?
Nondisjunction of oocyte
What is the mode of inheritance for Huntington's disease?
Autosomal dominant
What is the outcome of nondisjunction in meiosis or mitosis?
Both a and b
Which mode of inheritance is most frequently seen in males?
X-linked recessive
Which genetic disorder is an example of X-linked dominant inheritance with incomplete penetrance?
Fragile X Syndrome
What type of genetic trait results in the appearance of both alleles as distinct phenotypes in an individual?
Co-dominance
Which genetic disorder is associated with fewer functional LDL receptors, causing more LDL left in the bloodstream?
Familial Hypercholesterolemia
Which genetic disorder is an example of a heterozygote advantage, where the influence of a recessive gene improves survival?
Sickle cell trait
Which genetic disorder is associated with genomic imprinting, where only one copy of a gene in an individual is expressed while the other copy is suppressed?
Prader-Willi Syndrome
Which type of genetic trait involves the modification of gene expression rather than alteration of the genetic code itself?
Epigenetics
What is the primary function of mitogens in cellular reproduction?
To increase cell mass or growth by promoting the synthesis of protein and other macromolecules
Which phase of the cell cycle is characterized by the doubling of mass and duplication of all its contents?
Interphase
What process occurs in both spermatogenesis and oogenesis, resulting in the formation of haploid cells?
Meiosis
Which type of cell contains 46 chromosomes in the nucleus and is formed through mitosis?
Somatic cells
During which phase of mitosis do spindle fibers pull on chromosomes, causing centromeres to become aligned in the middle of the spindle?
Metaphase
What is the primary role of survival factors in cellular reproduction?
To promote cell survival by suppressing apoptosis
What is the main cause of Prader-Willi syndrome?
Microdeletion on maternal chromosome 15
What are the genetic causes of Angelman syndrome?
Silencing of maternal genes due to DNA methylation
Which genetic disorder does not exhibit genetic anticipation?
Prader-Willi syndrome
Which genetic disorder is caused by triplet repeat expansion on the X chromosome?
Fragile X syndrome
Which protein is affected in Fragile X syndrome?
FMRP
Which gene is affected in Prader-Willi syndrome?
SNRPN
Which of the following is not a clinical manifestation of Prader-Willi syndrome?
Limited speech
Which of the following is not a clinical manifestation of Angelman syndrome?
Hypogonadism
Which of the following disorders is not associated with triplet repeat expansion?
Angelman syndrome
Which genetic disorder is most frequently associated with microdeletion on the maternal chromosome 15?
Angelman syndrome
What type of carbohydrates cannot be digested by the human body?
Cellulose
Which fatty acids are essential for humans and cannot be produced by the body?
Linoleic acid and Linolinic acid
What is the main function of proteins in the body?
Maintain cell structure
Which amino acids are considered nonessential because the body can produce them?
Alanine and Asparagine
What system delivers absorbed nutrients to the liver for processing before entering the general circulation?
Hepatic Portal System
What structures in the small intestine increase the surface area for better nutrient absorption?
Microvilli
What is the primary role of the Na+/K+ pumps at the base of intestinal villus cells?
Pump sodium out of the cell
In which phase does the absorbed sodium move into intestinal cells through a transporter from the GI lumen?
Absorption Phase
Which term describes the situation when Energy Intake is less than the Internal heat produced, External work performed, and Energy stored?
Negative Energy Balance
What is characteristic of Metabolically Healthy Obesity (MHO) in individuals?
Decreased risk for morbidity and mortality
Which individuals are more likely to exhibit Metabolically Healthy Obesity (MHO)?
Individuals with high insulin sensitivity
What is the primary difference between White and Brown fat in terms of efficiency?
Brown fat burns more efficiently than White fat
What is one function of Uncoupling proteins related to fat utilization?
Protect the heart and vessels from oxidative stress
What does the term 'Metabolic Rate Control of Hunger and Food Intake is complicated' mean in the context of the text?
Several factors affect metabolic rate and hunger regulation
Which factor does NOT contribute to the complexity of an individual's relationship with food according to the text?
Height and weight correlation
What is the main focus when discussing Metabolically Healthy Obesity (MHO) according to the text?
Lack of metabolic syndrome
What process allows the production of ATP during catabolism?
The transfer of electrons in the mitochondrial membrane
Which step of anabolism does not require energy from ATP?
The assembly of complex molecules
Which macronutrient can be directly converted into acetyl CoA without breaking into monomers?
Fats
Which process allows the synthesis of lipids during anabolism?
All of the above
What is the primary role of NADH during catabolism?
To transport electrons to the mitochondrial membrane
What is the function of the citric acid cycle during catabolism?
To generate electron carriers for the electron transport chain
Which macronutrient is the primary source of energy during anabolism?
Carbohydrates
Which step of catabolism is responsible for the conversion of pyruvate into acetyl CoA?
Pyruvate oxidation
What is the role of the exocrine pancreas in digestion?
To release bicarbonate into the duodenum and enzymes for digesting macronutrients
What type of molecules are transported across the intestinal cells using the movement of sodium through a sodium channel?
Monosaccharides
Which enzyme is responsible for breaking down polysaccharides in the digestive system?
Amylase
What happens to fat droplets in the small intestine before they can be absorbed?
They are broken down into monoglycerides and free fatty acids by lipase
What is the role of the microvilli in the digestive system?
To provide a large surface area for absorption
Which of the following is not a type of macronutrient?
Enzymes
What is the primary role of bicarbonate released by the exocrine pancreas?
To neutralize stomach acid in the duodenum
How do free amino acids enter epithelial cells in the digestive system?
Coupled to sodium through a sodium channel
What is the primary function of intrinsic factor in vitamin B12 absorption?
To bind to vitamin B12 in the small intestine and facilitate its absorption in the distal ileum
Which hormone is responsible for converting macronutrients to triglycerides in fat cells during the absorptive state?
Insulin
What happens to plasma glucose levels during the postabsorptive state despite no recent meal intake?
Plasma glucose levels remain constant between 70-110 mg/dl
Which hormonal system is activated during insulin resistance, resulting in higher cholesterol levels and changes in fat storage?
The cortisol and sympathetic nervous system
Which target tissue is primarily responsible for converting glucose to glycogen during the absorptive state under optimal insulin levels?
The muscle cells
What role does glucagon play in energy homeostasis during exercise and stress?
Glucagon increases, promoting the breakdown of glycogen and gluconeogenesis
Which hormone is responsible for echoing the actions of epinephrine and norepinephrine in contributing to elevated glucose levels and protein breakdown during chronic stress or insulin resistance?
Cortisol
Which tissue is responsible for performing gluconeogenesis and producing ketones for the nervous system during the postabsorptive state?
The liver
What is the main function of Albumin in the bloodstream?
Regulating water and solute passage through capillaries
What is the primary role of immunoglobulins in plasma?
Defense against infection
Which component is responsible for creating oncotic pressure to keep fluid in the vasculature?
Immunoglobulins
Where are plasma proteins like clotting factors and fibrinogen primarily produced?
Liver
Which blood cell is responsible for carrying oxygen to tissues in the body?
Red Blood Cells (RBCs)
What is the primary function of fibrinogen in the bloodstream?
Playing a role in blood clotting
Which of the following components in blood is responsible for defense mechanisms against infections?
White Blood Cells (WBCs)
What is the critical function of plasma proteins related to clotting factors?
Clotting
In the bloodstream, which component aids in binding and carrying molecules like iron, copper, and vitamins?
Plasma proteins
Which of the following is responsible for maintaining colloidal osmotic pressure within blood vessels?
Immunoglobulins
Which hematopoietic precursor lineage does not continue differentiation through proliferation?
Megakaryocytes
Which site in the human body is responsible for producing the majority of erythropoietin in response to hypoxia?
Kidneys
What important molecule, produced by the enterocytes of the duodenum, is involved in the transport and absorption of iron in the human body?
Transferrin
Which of the following bone marrow types is primarily responsible for active hematopoiesis in adults?
Red marrow
Which of the following is the correct combination of heme groups and polypeptide chains in hemoglobin?
Two α and two β chains, with each chain carrying one iron ion
What is the primary site of fibrin formation in the human body?
Blood vessels
Which substance is responsible for maintaining homeostatic pH levels in the human body by transporting carbon dioxide?
Carbonic anhydrase
What factor, primarily produced by the liver in the process of inflammation, can lead to the destruction of red blood cells?
C-reactive protein
Which vitamin is crucial for the intracellular metabolism of propionic acid, which is derived from odd-chain fatty acids and certain amino acids?
Vitamin B12
Which substance can be used as a treatment for iron deficiency anemia to help stimulate erythropoiesis?
Erythropoietin
Which white blood cell primarily resides in secondary lymphoid tissues after entering the bloodstream?
Lymphocyte
Which white blood cell is crucial for cell-mediated immunity and activated by CD4 T-Helper cells?
Cytotoxic T-Cells
Which white blood cell contains heparin, histamine, and other inflammatory factors and is involved in allergic and hypersensitivity reactions?
Basophil
What is the primary role of type 1 hypersensitivity reactions and asthma in the body?
Characterized by high numbers of circulating eosinophils
What is the primary function of NK cells in the body?
Innate immunity
Which white blood cell is responsible for transforming into macrophages and traveling to sites of inflammation?
Monocyte
What is the primary role of the macrophages in the body?
Wound healing and tissue remodeling
Which blood disorder is characterized by a reduction in the effective production of mature cells of bone marrow causing peripheral pancytopenia anemia, neutropenia, and thrombocytopenia?
Aplastic anemia
What is the primary treatment for Aplastic Anemia?
Bone marrow transplant and immunosuppression
What are the causes of Aplastic Anemia?
Auto-immune, chemicals, drugs, radiation, viral infections (Hepatitis, CMV, Varicella), Inherited (Fanconi Anemia)
What is the primary component of hemoglobin that is broken down into its component amino acids?
Globin
What is the term for the process of Oxygen binding to hemoglobin with a domino effect, where the second molecule binds more easily after the first one?
Cooperative binding
What is the primary function of thrombopoietin (TPO) in platelet synthesis?
Stimulating platelet synthesis
What is the primary function of granulocytes in the immune system?
Phagocytosis and killing microorganisms
What is the term for the process by which bilirubin is converted to a water-soluble form in the liver?
Conjugation
What is the primary location where platelets are stored and released into circulation only when needed?
Spleen
What is the term for the curve that shows the relationship between oxygen saturation of hemoglobin and the partial pressure of oxygen?
Hemoglobin saturation curve
What is the primary factor that influences the release of thrombopoietin (TPO) from the liver, kidney, smooth muscle, and bone marrow?
Level of circulating platelets
What is the term for the process by which oxygen is transported in a dissolved state in plasma, which is critical in situations like CO poisoning?
Dissolved oxygen transport
What is the primary function of leukocytes in the immune system?
Defending against microorganisms and foreign substances
What is the primary role of Thromboxane A2 (TXA2) in platelet activation?
Stimulating more platelet activation
In the clotting cascade, which factor is responsible for converting prothrombin into thrombin?
Factor X
What is the primary function of Tissue Factor Pathway Inhibitor (TFPI) in blood clotting?
Inhibiting blood clotting initiation
Which vitamin is essential for the activation of clotting factors and is antagonized by Warfarin (coumadin)?
Vitamin K
What effect does Aspirin have on thromboxane A2 (TXA2) production and platelet activation?
Decreases TXA2 production
Which of the following is NOT a vitamin K-dependent clotting factor?
Factor VIII
What is the primary role of Factor XII in the intrinsic pathway of the clotting cascade?
Starting the common pathway
Which of the following plays a significant role in lysis of blood clots by degrading fibrin into fibrin degradation products?
Plasminogen
In vessel injury, which receptor binds with high affinity to Tissue Factor (TF) to initiate the clotting pathway?
Factor VII
What is a significant deficiency that leads to mild bleeding in hemophilia C?
Factor XI deficiency
What is the primary function of von Willebrand Factor (vWF) in hemostasis?
To mediate platelet adhesion
What happens to the vessel after platelets stick to the site of endothelial damage?
It narrows due to increased shear forces
What is the result of endothelial damage in hemostasis?
Release of thromboxane A2 (TXA2) and activation of endothelial cells
What is the role of platelet plug in hemostasis?
To provide a temporary physical barrier to bleeding
What is the ultimate result of the clotting system activation in hemostasis?
Formation of a fibrin clot
What is the function of endothelium in normal conditions?
To actively regulate blood flow and suppress spontaneous activation of platelets and the clotting system
What mediates platelet adhesion to the subendothelial matrix?
Glycoprotein Ib (GPIb) binding to von Willebrand Factor (vWF)
What is the result of fibrinolysis activation?
Beginning of the healing process
What happens to the fibrin clot during the healing process?
It contracts to form a more permanent plug
What is the main consequence of G6PD deficiency in red blood cells?
Decreased production of Glutathione
How do red blood cells in individuals with G6PD deficiency primarily respond to oxidative stress?
Increased susceptibility to hemolytic anemia
What is the primary function of the Hexose Monophosphate Shunt (Pentose Phosphate Pathway) in red blood cells?
Generating NADH for detoxifying free radicals
In individuals without G6PD deficiency, how does the Hexose Monophosphate Shunt differ in its role?
Serves as the primary source of ATP production
What is the significance of NADH production via the Hexose Monophosphate Shunt in red blood cells?
Detoxifies Reactive Oxygen Species (ROS)
Which of the following triggers can induce hemolytic anemia in individuals with G6PD deficiency?
Consumption of broad beans like fava beans
What cellular damage is minimized by the production of NADH through the Hexose Monophosphate Shunt?
Oxidative stress
How does G6PD-deficient red blood cell function differ from that of healthy cells under oxidative stress?
Heightened vulnerability to hemolysis
Which condition is a potential consequence of G6PD deficiency and exposure to methylene blue?
Hemolytic anemia
What symptoms may be exhibited by individuals with G6PD deficiency upon exposure to trigger substances?
Fatigue, jaundice, and hemolytic anemia
What type of anemia results from a problem with hemoglobin synthesis and is characterized by microcytic and hypochromic cells?
Microcytic-hypochromic anemia
What is the primary mechanism by which the redundancy of the genetic code guards against mutations?
Degeneracy
Which type of anemia is primarily caused by a problem with red blood cell maturation from precursor cells, resulting in macrocytic cells?
Megaloblastic anemia
What is the primary cause of normocytic-normochromic anemia?
Bone marrow suppression
Which genetic disorder does not exhibit genetic anticipation?
Friedreich's ataxia
What hormone is responsible for converting macronutrients to triglycerides in fat cells during the absorptive state?
Insulin
What genetic disorder does not result from a deletion on chromosome 15q11-13?
Klinefelter syndrome
Which vitamin is essential for the intracellular metabolism of propionic acid, which is derived from odd-chain fatty acids and certain amino acids?
Vitamin B12
Which step of anabolism does not require energy from ATP?
Protein synthesis
Which genetic disorder is an example of X-linked dominant inheritance with incomplete penetrance?
Rett syndrome
Which of the following anemia types is characterized by microcytic-hypochromic abnormal erythrocytes with reduced amounts of Hb?
Iron Deficiency Anemia (IDA)
In the context of Polycythemia, what is the function of erythroid precursor cells in bone marrow?
They proliferate independently of EPO
What are the primary causes of the Enzyme deficiency that leads to hemolytic anemia?
Physical trauma and genetic mutations
Which type of anemia results from a decreased erythrocyte life span, suppressed production of EPO, ineffective bone marrow erythroid progenitor response, altered iron metabolism, and sequestration in macrophages?
Anemia of Chronic Disease
Which type of anemia results from autoimmune antibody-mediated destruction?
Hemolytic Anemia
Which of the following is a cause for increased RBC Destruction in Hemolytic Anemia?
Prosthetic heart valves
Which genetic disorder results from triplet repeat expansion on the X chromosome?
Huntington's disease
What happens to plasma glucose levels during the postabsorptive state despite no recent meal intake?
Plasma glucose levels first increase then stabilize
What is the function of NK cells in the body?
NK cells are responsible for the destruction of virally infected and tumor cells
Which factor does NOT contribute to the complexity of an individual's relationship with food according to the text?
Personal food preferences
Study Notes
Blood Composition
- Blood is composed of 55% plasma, which is 90% water, and 45% formed elements (cells)
- Plasma proteins:
- Albumin: regulates passage of water and solutes through capillaries, maintains colloidal osmotic pressure
- Immunoglobulins: produced by plasma cells in lymph nodes, involved in defense
- Fibrinogen: involved in clotting
- Cellular components:
- Red blood cells (RBCs, erythrocytes)
- White blood cells (WBCs, leukocytes)
- Platelets (thrombocytes)
Functions of Blood
- Maintains acid-base balance
- Major transportation route for oxygen, nutrients, and hormones
- Removes carbon dioxide and waste products
- Maintains body temperature
- Provides defense against infection
Plasma Proteins
- Functions:
- Clotting: clotting factors and fibrinogen
- Defense: antibodies and complement proteins
- Transport: bind and carry various molecules (e.g., iron, copper, steroid hormones, vitamins, lipids)
- Regulation: protein hormones that communicate between cells
Hematopoiesis (Blood Cell Production)
- Occurs in bone marrow
- Body requires 100 billion new blood cells per day
- Hematopoietic stem cells (HSCs) can differentiate into:
- RBCs: oxygen transport
- WBCs: immunity
- Platelets: tissue remodeling
Bone Marrow
- Primary site of hematopoietic stem cells
- Composition:
- Red marrow (active, hematopoietic, aka myeloid tissue)
- Yellow marrow (inactive, large amount of fat)
Cellular Differentiation
- Pluripotent stem cells develop into:
- Erythrocytes (RBCs)
- Granulocytes (neutrophils, monocytes)
- Lymphocytes (T cells, B cells, NK cells)
- Megakaryocytes (platelets)
Erythrocytes (RBCs)
- Characteristics:
- No nucleus
- Thin, biconcave disks
- No mitochondria, use fermentation energy
- Carry carbonic anhydrase, important for maintaining pH homeostasis
- Lifespan: approximately 120 days
- Maturation: from erythroblasts to reticulocytes to mature RBCs
- Erythropoietin (EPO): hormone that increases RBC production, made in kidneys, liver
Hemoglobin
- Composition: 2 α and 2 β polypeptide chains, central Fe+ ion
- Function: carries oxygen
- Heme group: molecule that contains iron ion, capable of reversibly binding oxygen
Iron
- Absorption:
- Dietary sources: meat, vegetables, iron-fortified foods
- Improved by vitamin C
- Regulated based on body's needs
- Storage:
- Primarily in liver and bone marrow
- Ferritin: storage form of iron
- Circulation:
- Bound to transferrin
- Unbound transferrin indicates low iron levels
Leukocytes (WBCs)
- Types:
- Neutrophils: involved in defense against fungi, bacteria, and foreign substances
- Eosinophils: involved in allergic reactions and parasitic infections
- Basophils: involved in allergic reactions
- Lymphocytes: involved in immune response
- Monocytes: mature into macrophages
Platelets (Thrombocytes)
- Characteristics:
- Small, anucleate cell fragments
- Membrane-enclosed sacs of cytoplasm
- Contain dense granules
- Synthesized in response to thrombopoietin (TPO)
- Functions:
- Defend against microorganisms
- Initiate wound healing and tissue remodeling
Blood Clotting
- Process:
- Intrinsic pathway: activated within the blood vessel
- Extrinsic pathway: activated by tissue factor
- Common pathway: leads to formation of fibrin clot
- Vitamin K-dependent clotting factors:
- Prothrombin (factor II)
- Factor VII
- Factor IX
- Factor X
- Protein C and S
Hemostasis
- Definition: the arrest of bleeding by the formation of blood clots at sites of vascular injury
- Components:
- Vasculature: endothelium and subendothelium
- Platelets: activation and aggregation
- Blood proteins: clotting factors
- Process:
- Injury → vasoconstriction
- Endothelial damage → platelet adhesion and activation
- Tissue factor and platelet factors → activate clotting system
- Formation of fibrin clot
- Fibrinolysis: breakdown of clot
Fibrinolysis
- Primary mechanism: plasminogen-plasmin system
- Components:
- Plasminogen: produced in the liver
- Tissue plasminogen activator (t-PA): activates plasminogen
- Plasmin: degrades fibrin in clots
- Fibrin degradation products (FDPs): resulting from plasmin activity
- D-dimer: a specific FDP### Anemia
- Macrocitic anemia: caused by B12 deficiency, pernicious anemia, and anemia of chronic disease
- Microcytic anemia: caused by iron deficiency anemia (most common cause), lead poisoning, and sideroblastic anemia
- Iron deficiency anemia: caused by impaired absorption, increased requirement, and chronic blood loss
- Hemolytic anemia: caused by autoimmune antibody-mediated destruction, traumatic hemolysis, infectious hemolysis, and physical hemolysis
- Hereditary forms: enzyme deficiencies (e.g. G6PD), sickle cell anemia, and hemoglobin variants
Hemoglobin Variants
- Hemoglobin A: normally over 95% of an adult's hemoglobin
- Hemoglobin A2: has a normal adult range of 1.5-3.5%
- Hemoglobin F: fetal hemoglobin, restricted to a limited population of red cells
- Thalassemia: being "less" one type of globin chain
- Alpha thalassemia: missing one or more alpha globin chains
- Beta thalassemia: missing one or more beta globin chains
- Pathologic hemoglobin variants:
- Hemoglobin H: four β chains joined together (β4)
- Hemoglobin Barts: four γ chains joined together (Υ4)
Polycythemia
- Excessive red blood cell production
- Relative hemoconcentration due to dehydration, diarrhea, excessive vomiting, and diuretics
- Absolute: primary polycythemia vera, erythroid precursor cells in bone marrow proliferate independent of EPO
- Secondary: due to increased production of EPO due to chronic hypoxemia
- Clinical manifestations: splenomegaly, increased blood viscosity, plethora, and engorgement of the retinal and cerebral veins
Methemoglobin
- Hemoglobin that exists with its iron as Fe+3 rather than Fe+2
- Occurs when Hb is exposed to oxidative stressors
- Causes: hemoglobin variants, cytochrome b5 reductase deficiency, toxic substances, and acquired methemoglobinemia
- Clinical presentation: dyspnea, cyanosis, and hypoxemia that is refractory to supplemental oxygen
Glycolysis and the Red Blood Cell
- Glucose is the only fuel RBCs can use
- Embden-Meyerhof pathway: converts glucose to pyruvate
- Hexose monophosphate shunt: generates NADH, which is a reducing agent that detoxes free radicals
- G6PD deficiency: genetic absence of G6PD, leads to hemolytic anemia
Anemia Classifications
- Changes to RBC size or Hb content:
- Microcytic-hypochromic: caused by iron deficiency anemia
- Macrocytic: caused by B12 or folate deficiency
- Normocytic-normochromic: caused by blood loss anemia
- Mechanisms of anemia:
- Blood loss: acute or chronic
- Decreased RBC production: due to ineffective erythrocyte DNA synthesis
- Increased RBC destruction: due to hemolysis or sequestration
DNA and Genetics
- DNA replication: occurs in the nucleus during cell division
- DNA polymerase: enzyme that travels along the single DNA strand and adds the correct nucleotides to the free end of the new strand
- DNA ligase: enzyme that joins small fragments of DNA to form a continuous chain
- Genetic code: redundant, unambiguous, and nearly universal
- Transcription: process that synthesizes RNA from a DNA template in the nucleus
- Translation: process during which RNA directs the synthesis of a polypeptide
- Mutations: inherited alteration of genetic material
- Point mutation: a base pair substitution
- Frameshift mutation: insertion or deletion of one or more base pairs
- Gene expression: controlled by the level of transcription
- DNA packing: DNA is wrapped around a histone protein
- Differentiation: results from selective gene expression### Modes of Inheritance
- X-Linked Dominant Disorders: rare, example is Fragile X Syndrome with incomplete penetrance
- X-Linked Recessive Disorders: more common, examples include hemophilia and baldness
Co-Dominance and Incomplete Dominance
- Co-Dominance: two versions of an allele are expressed separately, yielding different traits in the individual
- Example: ABO Blood Typing, where both A and B alleles are expressed equally
- Incomplete Dominance: neither allele is dominant over the other, resulting in an intermediate phenotype
- Example: Familial Hypercholesterolemia, caused by a mutation in LDL receptors
Polygenic Traits
- Multiple genes influence one trait
- Do not follow the patterns of Mendelian inheritance
- Can be influenced by the environment
- Examples: Height, Skin Color, Cancer, Diabetes, and Heart Disease
Evolution of Genetics
- If a genetic trait is advantageous, it is more likely to be passed to the next generation
- Over time, the advantageous trait becomes increasingly common in a population
- Example: heterozygote advantage, such as sickle cell trait providing protection against malaria
Epigenetics
- Study of changes in organisms caused by modification of gene expression
- Not a change in the genetic code itself
- Types of epigenetic changes:
- DNA Methylation: adds a methyl group to DNA, blocking transcription
- Histone Modification: chemical groups added or removed from histones, affecting gene expression
- Non-coding RNA: regulates gene expression
- Genomic Imprinting: only one copy of a gene is expressed, while the other copy is suppressed
Cell Reproduction
- Cellular reproduction: the most fundamental task for generating life
- Cell cycle: Interphase, M phase, Cytokinesis
- Types of cells:
- Germline cells: gametes (sperm and egg cells)
- Somatic cells: all other cells, contain 46 chromosomes
Meiosis
- Process of gamete formation
- Occurs in: Spermatogenesis, Oogenesis
- Two rounds of cell division: Meiosis I and Meiosis II
- Yields 4 haploid cells (gametes)
Genetic Disorders
- Prader-Willi Syndrome: microdeletion of paternal chromosome 15
- Angelman Syndrome: microdeletion of maternal chromosome 15
- Genetic Anticipation: genetic disorders that become more severe and appear at an earlier age in subsequent generations
Macronutrients
- Carbohydrates: provide 4 calories per gram, preferred method of energy extraction
- Lipids: provide 9 calories per gram, concentrated source of energy
- Proteins: provide 4 calories per gram, necessary for production of new tissue
Digestion and Absorption
- Absorption: Hepatic Portal System, delivers absorbed nutrients to the liver for processing
- Absorption in the Small Intestine: villi, microvilli, and Na+/K+ pumps
Energy Balance
- Energy Intake = Internal heat produced + External work performed + Energy stored
- Positive Energy Balance: high storage
- Negative Energy Balance: burning of stores
Metabolic Rate and Health
- Metabolic Rate Control: complicated, influenced by genetics, social and environmental barriers, access to clean water, poverty, food insecurity, mental health status, and more
- Hold space for individual experiences within these factors
- Remember that health is not 100% in an individual's control
Explore the structure of the cell nucleus and the organization of DNA into chromosomes. Learn about the components of the nucleus, including the outer and inner membranes, nucleolus, RNA, and DNA binding proteins. Understand the relationship between genes, histone proteins, and the synthesis of specific proteins.
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