Chemistry Exam 2 (Ch 6, 9, 13-17, 27)

What is transferrin?

Transferrin is the major iron transport protein in plasma.

Function:

• Transports iron (Fe³⁺) through the blood

• Delivers iron to tissues and bone marrow for hemoglobin production

Would transferrin levels be low in iron deficiency?

No. Transferrin is usually increased in iron deficiency anemia.

Condition	Transferrin
Iron deficiency	↑ Increased
Chronic disease/inflammation	↓ Decreased

Reason:

• The body makes more transferrin to capture available iron.

What is ferritin?

Ferritin is the body's major iron storage protein.

Function:

• Stores iron in liver, spleen, and bone marrow

• Reflects total body iron stores

High-yield:

Condition	Ferritin
Iron deficiency	↓ Low
Iron overload	↑ High

What does lead affect in the body?

Lead interferes with heme synthesis.

Lead inhibits:

1. Delta-aminolevulinic acid dehydratase (ALA dehydratase)

2. Ferrochelatase

Results:

• Decreased heme production

• Anemia

• Increased zinc protoporphyrin

• Neurologic symptoms

How many carbons are in a pentose carbohydrate?

5 carbons

Is maltose a monosaccharide or disaccharide?

Disaccharide

Is sucrose a reducing sugar?

Sucrose is a nonreducing sugar.

What hormone lowers blood glucose levels?

Insulin

What must be done with glucose for it to be used in metabolic pathways?

It must enter cells and undergo metabolism.

Know the pathways of glucose metabolism.

✅ Glycolysis = glucose → pyruvate

✅ Glycogenesis = glucose → glycogen

✅ Glycogenolysis = glycogen → glucose

✅ Gluconeogenesis = non-carbohydrates → glucose

✅ Pentose phosphate pathway = NADPH and ribose production

What does glucagon do?

Raises blood glucose

Actions:

• Glycogenolysis

• Gluconeogenesis

Know the actions of glucagon and insulin.

Insulin

✅ Lowers glucose

• Increases glycogenesis

• Increases glycolysis

• Increases glucose uptake

Glucagon

✅ Raises glucose

• Increases glycogenolysis

• Increases gluconeogenesis

What does cortisol do? When is it highest?

✅ Raises blood glucose

✅ Stimulates gluconeogenesis

✅ Opposes insulin

Highest:

✅ Early morning

Compare Type 1 and Type 2 Diabetes Mellitus.

Type 1	Type 2
Autoimmune	Insulin resistance
Absolute insulin deficiency	Relative insulin deficiency
Ketones present	Usually absent
DKA common	HHS common

Laboratory findings of hyperglycemia

✅ Increased plasma glucose

✅ Glycosuria

✅ Ketonuria

✅ Increased Hemoglobin A1c

✅ Elevated osmolality

Risk factors for Type 2 Diabetes Mellitus

✅ Obesity

✅ Family history

✅ Hypertension

✅ Physical inactivity

✅ African American ethnicity

✅ Previous gestational diabetes

How is diabetes diagnosed?

✅ Fasting plasma glucose ≥126 mg/dL

✅ Hemoglobin A1c ≥6.5%

✅ Random glucose ≥200 mg/dL with symptoms

✅ 2-hour Oral Glucose Tolerance Test ≥200 mg/dL

Interpret a 2-hour Oral Glucose Tolerance Test

Result	Interpretation
<140 mg/dL	Normal
140-199 mg/dL	Prediabetes
≥200 mg/dL	Diabetes

What is hypoglycemia?

Plasma glucose less than approximately 60 mg/dL

Symptoms:

• Shaking

• Sweating

• Confusion

• Dizziness

Two major glucose measurement methods

✅ Hexokinase (reference method)

✅ Glucose oxidase

What is Hemoglobin A1c?

✅ Glycosylated hemoglobin

Reflects:

✅ Average glucose over previous 2-3 months

List the three ketone bodies.

✅ Acetoacetate

✅ Beta-hydroxybutyrate

✅ Acetone

What can increased ketones indicate?

✅ Diabetic Ketoacidosis

✅ Starvation

✅ Fasting

✅ Prolonged vomiting

✅ Increased fat metabolism

What enzyme is missing in PKU?

Phenylalanine hydroxylase

What enzyme deficiency causes homogentisic acid accumulation?

✅ Homogentisate oxidase

Disease:

✅ Alkaptonuria

List 5 functions of proteins.

✅ Transport

✅ Immunity

✅ Enzymes

✅ Maintenance of oncotic pressure

✅ Blood clotting

Largest plasma protein fraction? How much?

✅ Albumin

✅ About 60% of total plasma proteins

What is prealbumin?

Transthyretin

Function:

• Nutritional marker

• Transports thyroxine and retinol-binding protein

Albumin reference range

3.5-5.5 g/dL

Where are most proteins made?

✅ Liver

Exception:

✅ Immunoglobulins → Plasma cells

Name an Alpha-1 band protein.

Alpha-1 antitrypsin

Name a globulin in the Alpha-2 band.

✅ Haptoglobin

✅ Ceruloplasmin

✅ Alpha-2 macroglobulin

Name a protein in the Beta fraction.

Transferrin

Name three acute phase reactants.

✅ C-reactive protein

✅ Haptoglobin

✅ Ceruloplasmin

When do acute phase reactants increase?

✅ Inflammation

✅ Infection

✅ Trauma

✅ Tissue injury

Draw a normal serum protein electrophoresis pattern.

Order from anode (+) to cathode (-)

Albumin → Alpha-1 → Alpha-2 → Beta → Gamma

Hypothalamic-Pituitary-Thyroid Axis

Four direct effector hormones secreted by the pituitary

✅ Growth Hormone

✅ Prolactin

✅ Antidiuretic Hormone (Vasopressin)

✅ Oxytocin

One action of Growth Hormone

Stimulates growth and protein synthesis

What is vasopressin?

✅ Antidiuretic Hormone (ADH)

Function:

✅ Promotes water reabsorption in kidney collecting ducts

What is Diabetes Insipidus?

Deficiency of Antidiuretic Hormone or renal resistance to it.

Findings:

• Excessive urination

• Excessive thirst

Where are adrenal glands located?

On top of each kidney

Precursor of adrenal hormones

Cholesterol

Three zones of adrenal cortex

✅ Zona Glomerulosa

✅ Zona Fasciculata

✅ Zona Reticularis

Hormones produced in each zone

Zona Glomerulosa

✅ Aldosterone

Zona Fasciculata

✅ Cortisol

Zona Reticularis

✅ Androgens

Hyperaldosteronism does what to potassium?

Causes hypokalemia

(low potassium)

What is cortisol for?

✅ Stress response

✅ Increases glucose

✅ Promotes gluconeogenesis

Highest:

✅ Early morning

Hypercortisolism is known as?

✅ Cushing Syndrome

Diagnosis:

✅ Dexamethasone suppression test

Physical features of Cushing Syndrome

✅ Moon face

✅ Buffalo hump

✅ Central obesity

✅ Purple striae

What are adrenal androgens?

✅ Dehydroepiandrosterone (DHEA)

✅ Androstenedione

What does adrenal medulla secrete?

✅ Epinephrine

✅ Norepinephrine

Hormone promoting breast, uterine, and vaginal development

Estrogen

Hormone inducing secretory activity of endometrial glands

Progesterone

Two phases of menstrual cycle

✅ Follicular phase

✅ Luteal phase

Infertility + hirsutism + chronic anovulation + glucose intolerance + hyperlipidemia + hypertension suggest?

Polycystic Ovary Syndrome (PCOS)

What two hormones are produced by the thyroid?

Thyroxine (T4)

✅ Triiodothyronine (T3)

What controls calcium levels?

✅ Parathyroid Hormone (PTH)

✅ Calcitonin

✅ Vitamin D

Most common cause of hypothyroidism in developing countries

Iodine deficiency

What does the thyroid use iodine for?

Synthesis of T3 and T4

In hyperthyroidism, TSH is low or high?

Low

(due to negative feedback)

Most common cause of hyperthyroidism

Graves Disease

Two autoimmune thyroid diseases

✅ Graves Disease

✅ Hashimoto Thyroiditis

Signs and symptoms of hypothyroidism

✅ Fatigue

✅ Weight gain

✅ Cold intolerance

✅ Bradycardia

✅ Constipation

Treatment:

✅ Levothyroxine (T4)

Signs and symptoms of hyperthyroidism

✅ Weight loss

✅ Heat intolerance

✅ Tachycardia

✅ Nervousness

✅ Tremors

Treatment:

✅ Methimazole

✅ Radioactive iodine

✅ Thyroid surgery

✅ Transferrin = iron transport

✅ Ferritin = iron storage

✅ Lead inhibits heme synthesis

✅ Insulin lowers glucose

✅ Glucagon raises glucose

✅ Hexokinase = reference glucose method

✅ Hemoglobin A1c = 2-3 month average

✅ PKU = phenylalanine hydroxylase deficiency

✅ Alkaptonuria = homogentisate oxidase deficiency

✅ Albumin = 60% of plasma proteins

✅ Ceruloplasmin transports copper

✅ SPE order = A A A B G

✅ Cortisol highest in morning

✅ Diabetes Insipidus = Antidiuretic Hormone problem

✅ Adrenal zones = GFR

✅ Aldosterone → lowers potassium

✅ Hypercortisolism = Cushing Syndrome

✅ Graves = hyperthyroidism

✅ Hashimoto = hypothyroidism

✅ Iodine needed for T3/T4 synthesis