Unlock hundreds more features
Save your Quiz to the Dashboard
View and Export Results
Use AI to Create Quizzes and Analyse Results

OR
Sign inSign in with Facebook
Sign inSign in with Google
Quizzes > Health & Medicine

2/3 mineral matter and what? Bone composition quiz

Quick, free bone composition quiz. Test your knowledge. Instant results.

Editorial: Review CompletedCreated By: Bethany BrennanUpdated Aug 28, 2025
Difficulty: Moderate
2-5mins
Learning OutcomesCheat Sheet
Paper art illustration of bone cross section showing mineral outer layer spongy inner layer red marrow on teal background

This quiz helps you check what makes up bone, including why it is 2/3 mineral matter and what forms the rest, like collagen and marrow. Practice key terms, compare compact and spongy bone, and go deeper with our bone tissue quiz, compact bone quiz, and haversian system quiz.

What is the primary inorganic mineral in the bone matrix?
Collagen
Chondroitin sulfate
Calcium carbonate
Hydroxyapatite
Bone's inorganic component is largely composed of hydroxyapatite crystals, a form of calcium phosphate. These crystals embed within the collagen matrix to provide rigidity and strength. Hydroxyapatite is responsible for bone's high compressive strength and plays a key role in mineral homeostasis.
Approximately what fraction of bone by weight is mineral matter?
3/4
1/3
1/2
2/3
By weight, mature bone is about two-thirds mineral and one-third organic matrix. The mineral portion is mainly hydroxyapatite, while the organic portion consists of collagen and proteins. This ratio gives bone both stiffness and some flexibility.
Which cell type is responsible for new bone formation?
Chondrocyte
Osteoblast
Osteoclast
Osteocyte
Osteoblasts are specialized cells that synthesize and secrete the organic components of bone matrix, including collagen. They also initiate mineralization by releasing vesicles containing calcium and phosphate. Once trapped in the matrix, they differentiate into osteocytes.
Which organic protein forms the majority of the bone's organic matrix?
Keratin
Elastin
Fibronectin
Type I collagen
Type I collagen is the most abundant protein in bone's organic matrix and provides tensile strength. It forms a fibrous scaffold that is mineralized by hydroxyapatite crystals. Defects in type I collagen can lead to brittle bone disease.
What type of bone tissue is predominantly found in the shafts of long bones?
Trabecular (spongy) bone
Woven bone
Elastic cartilage
Cortical (compact) bone
Cortical bone, also called compact bone, forms the dense outer layer of long bone shafts and provides strength for weight bearing. It has a tightly packed osteon structure. In contrast, trabecular bone is found at bone ends and inside vertebrae.
What fills the medullary cavity of adult long bones?
Red bone marrow
Cartilage
Yellow bone marrow
Fibrous connective tissue
In adults, the medullary cavity of long bones contains yellow marrow, which is rich in fat cells. Red marrow, where hematopoiesis occurs, is found mainly in flat bones and the ends of some long bones. Yellow marrow can convert back to red marrow in cases of severe blood loss.
Which vitamin is essential for calcium absorption and bone mineralization?
Vitamin A
Vitamin D
Vitamin C
Vitamin K
Vitamin D promotes intestinal absorption of calcium and phosphate, which are critical for bone mineralization. Without sufficient vitamin D, bones can become soft (rickets in children, osteomalacia in adults). It is activated in the kidneys to form calcitriol.
What hormone increases bone resorption to elevate blood calcium levels?
Calcitonin
Insulin
Growth hormone
Parathyroid hormone
Parathyroid hormone (PTH) is secreted by the parathyroid glands when blood calcium is low. It stimulates osteoclast activity to resorb bone and release calcium into the bloodstream. PTH also increases renal calcium reabsorption and activates vitamin D.
What term describes bone formation directly from mesenchymal tissue without a cartilage precursor?
Intramembranous ossification
Interstitial growth
Endochondral ossification
Appositional growth
Intramembranous ossification is the direct differentiation of mesenchymal cells into osteoblasts, forming flat bones like the skull and clavicle. It bypasses a cartilage stage. Endochondral ossification, by contrast, uses a cartilage model.
What are the small cavities that house osteocytes in bone called?
Osteons
Lamellae
Canaliculi
Lacunae
Lacunae are small cavities between lamellae in bone where osteocytes reside. These cells maintain bone tissue and communicate via canaliculi. Canaliculi are tiny channels linking lacunae for nutrient and waste exchange.
Which bone cell type is responsible for bone resorption?
Chondroblast
Osteoblast
Osteoclast
Fibroblast
Osteoclasts are large, multinucleated cells derived from monocyte/macrophage lineage. They secrete acids and proteolytic enzymes to dissolve mineral and organic bone matrix. This process is essential for bone remodeling and calcium homeostasis.
Besides collagen, which organic molecules contribute significantly to the bone matrix?
Actin
Myosin
Elastin
Proteoglycans
Proteoglycans are glycoproteins with glycosaminoglycan chains that attract water and resist compressive forces. They work alongside collagen to provide flexibility and resilience. Other non-collagenous proteins include osteocalcin and osteopontin.
In the growth plate, which zone is characterized by enlargement of cartilage cells?
Calcification zone
Resting zone
Hypertrophic zone
Proliferative zone
The hypertrophic zone of the epiphyseal growth plate features chondrocytes that enlarge and prepare matrix for mineralization. Following this, the calcification zone hardens the matrix before being replaced by bone. This process drives longitudinal growth.
What is the chemical formula of hydroxyapatite found in bone?
Ca10(PO4)6(OH)2
CaCO3
Ca5(PO4)3Cl
Ca3(PO4)2
Hydroxyapatite's chemical formula is Ca10(PO4)6(OH)2, representing calcium, phosphate, and hydroxide ions. It forms a crystalline structure that gives bone its hardness. Other calcium phosphates exist but are not the main bone mineral.
What fraction of bone weight is organic matrix (osteoid)?
1/3
2/3
1/2
3/4
The organic matrix, or osteoid, accounts for roughly one-third of bone's dry weight. It consists of collagen fibers and ground substance. Mineralization of osteoid turns it into rigid bone tissue. Imbalances can lead to osteomalacia or brittle bone.
Which element is the second most abundant mineral in bone after calcium?
Phosphorus
Potassium
Magnesium
Sodium
Phosphorus is the second most abundant mineral in bone, primarily as phosphate in hydroxyapatite crystals. Calcium and phosphate together form the mineralized component. Magnesium is present in smaller amounts and influences crystal growth.
Which protease secreted by osteoclasts degrades the organic bone matrix?
Cathepsin K
Trypsin
MMP-9
Elastase
Cathepsin K is a lysosomal cysteine protease highly expressed in osteoclasts. It degrades type I collagen in the bone matrix during resorption. Mutations in cathepsin K cause pycnodysostosis, a bone density disorder.
What is the name of the tiny channels through which osteocytes communicate?
Lamellae
Canaliculi
Trabeculae
Lacunae
Canaliculi are microscopic channels radiating from lacunae, connecting osteocytes within bone. They allow exchange of nutrients, wastes, and signaling molecules. This network sustains bone cell viability.
Which cytokine produced by osteoblasts stimulates osteoclast differentiation?
IL-6
TNF-?
BMP-2
RANKL
RANKL (Receptor Activator of Nuclear Factor ?B Ligand) is expressed by osteoblasts and stromal cells. It binds RANK on osteoclast precursors, promoting their maturation. Osteoprotegerin acts as a decoy receptor to inhibit this pathway.
During bone remodeling, which precursor cells fuse to form multinucleated osteoclasts?
Mesenchymal stem cells
Chondrocytes
Monocyte/macrophage lineage
Fibroblasts
Osteoclasts originate from hematopoietic stem cells that differentiate into monocyte/macrophage precursors. These precursors fuse under RANKL and M-CSF signaling to form multinucleated osteoclasts capable of resorbing bone.
What type of collagen crosslink enhances bone tensile strength?
Pyridinoline
Isopeptide
Hydroxylated
Disulfide
Pyridinoline crosslinks form between collagen molecules and increase tensile strength in bone and cartilage. They are mature, non-reducible crosslinks that stabilize the collagen matrix. Measurement of pyridinoline can indicate bone turnover.
Which trace mineral contributes to bone elasticity and is involved in crystal growth regulation?
Iron
Magnesium
Zinc
Copper
Magnesium is a cofactor for enzymes involved in bone metabolism and influences hydroxyapatite crystal size. About 60% of body magnesium is stored in bone. Deficiency can affect both bone strength and mineralization.
What is the primary effect of calcitonin on bone metabolism?
Stimulates bone formation
Inhibits bone resorption
Increases calcium absorption
Promotes phosphate release
Calcitonin, secreted by thyroid parafollicular cells, lowers blood calcium by inhibiting osteoclast activity. It reduces bone resorption and promotes calcium deposition in bone. Its physiological role in humans is less significant than PTH.
Which signaling pathway in osteoblasts is activated by mechanical stress to promote bone formation?
MAPK/ERK pathway
Hedgehog pathway
Notch pathway
Wnt/?-catenin pathway
Mechanical loading of bone activates Wnt/?-catenin signaling in osteoblasts, enhancing proliferation and matrix production. Sclerostin inhibition allows Wnt ligands to bind receptors and stabilize ?-catenin. This mechanism underlies bone's adaptive response to stress.
Which transcription factor is essential for osteoblast differentiation and is often abbreviated Runx2?
NFATc1
Sox9
Runt-related transcription factor 2
Osterix
Runx2 is a master regulatory transcription factor required for mesenchymal cells to differentiate into osteoblasts. Its expression triggers downstream genes for bone matrix proteins like osteocalcin. Knockout models lacking Runx2 fail to form bone.
0
{"name":"What is the primary inorganic mineral in the bone matrix?", "url":"https://www.quiz-maker.com/QPREVIEW","txt":"What is the primary inorganic mineral in the bone matrix?, Approximately what fraction of bone by weight is mineral matter?, Which cell type is responsible for new bone formation?","img":"https://www.quiz-maker.com/3012/images/ogquiz.png"}

Study Outcomes

  1. Understand Mineral Composition of Bone -

    Gain insight into how 2/3 of bone tissue is composed of mineral matter and why this ratio is critical for bone strength and rigidity.

  2. Describe Organic Components and Cells -

    Identify the roles of collagen, osteocytes, osteoblasts, and osteoclasts in maintaining bone tissue structure and function.

  3. Differentiate Bone Structure Types -

    Distinguish between compact and spongy bone architectures and explain their contributions to the skeletal system's support and protection functions.

  4. Explain Bone Marrow Functions -

    Understand the process of hematopoiesis and how red and yellow marrow within bones contribute to blood cell production and fat storage.

  5. Apply A&P Knowledge in the Quiz -

    Use your understanding of bone composition and structure to accurately answer bone tissue quiz and A&P bone tissue questions.

  6. Analyze Composition-Function Relationships -

    Correlate the mineral and organic makeup of bone with its mechanical properties and overall role in the skeletal system.

Cheat Sheet

  1. Mineral Matrix - Hydroxyapatite -

    About two-thirds of bone mass comes from hydroxyapatite [Ca10(PO4)6(OH)2], the crystalline calcium-phosphate salt that gives bone its rigidity (Guyton & Hall, 2021). A handy mnemonic is "10Cals, 6Puffs, 2OH" to recall the stoichiometry of Ca10(PO4)6(OH)2. This mineral matrix is what makes bone a standout question in your bone composition quiz.

  2. Organic Matrix - Type I Collagen -

    Roughly one-third of bone is organic collagen fibers, primarily Type I, which provide tensile strength and flexibility (NCBI Bookshelf). Think "Collagen is the backbone's shock absorber" when tackling A&P bone tissue questions. Without collagen, bone would be as brittle as a chalk stick.

  3. Bone Cells - OB, OC, OCy -

    Master the trio: Osteoblasts (build bone), Osteoclasts (crush/resorb bone), and Osteocytes (monitor bone matrix). Use the mnemonic "BOC" in your skeletal system quiz to keep them straight: Builders, Ousters, and Citizens of bone. Their coordinated work maintains bone homeostasis.

  4. Bone Marrow - Red vs. Yellow -

    Red marrow (hematopoietic) produces blood cells, while yellow marrow (fat storage) predominates in adults (American Society of Hematology). Remember "Red = Ready for blood" and "Yellow = Yummy fat" for quick recall in your bone tissue quiz. Changes in marrow composition are key to understanding bone health and aging.

  5. Bone Types - Compact and Spongy -

    Compact bone forms the dense outer shell; spongy (cancellous) bone features trabeculae that lighten weight and resist stress (Johns Hopkins University). Picture a honeycomb structure to remember spongy bone's strength-to-weight ratio. This distinction often appears on any bone composition quiz.

Make a Quiz (FREE) Copy & Edit This Quiz Create a Quiz with AI

Human Anatomy & Medicine Quizzes

Powered by: Quiz Maker