Biology Chapter on Extracellular Matrix and Glycoproteins

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Questions and Answers

What is the primary function of the extracellular matrix (ECM)?

Synthesizing new cellular components

Providing support and strength (correct)

Energy production for cellular processes

Facilitating cell division

What distinguishes proteoglycans from glycoproteins?

Proteoglycans are primarily proteins with added sugars

Proteoglycans are produced exclusively in the Golgi

Proteoglycans do not bind to proteins

Proteoglycans consist of long unbranched carbohydrate chains (correct)

In which cellular location does glycosylation of N-linked glycoproteins begin?

Cell membrane

Nucleus

Rough endoplasmic reticulum (correct)

Cytoplasm

What is the composition of glycosaminoglycans (GAGs)?

Negatively charged heteropolysaccharide chains Signup and view all the answers

What type of linkage occurs for sugars in O-linked glycoproteins?

Linked to serine or threonine Signup and view all the answers

Which process involves ATP leading to the release of actin from myosin?

When ATP binds to myosin head. Signup and view all the answers

What is the main role of Na,K-ATPase in muscle tissues?

To transport Na+ and K+ across the membrane using ATP. Signup and view all the answers

What causes the myosin heads to move during muscle contraction?

Splitting of ATP by creatine kinase. Signup and view all the answers

Which option correctly describes a feature of fast-twitch skeletal muscle fibers?

They easily tire due to limited blood supply. Signup and view all the answers

Where are stretch-activated calcium ion channels most likely found?

In unitary smooth muscle cells. Signup and view all the answers

What type of cells are primarily responsible for producing the extracellular matrix (ECM) in cartilage?

Chondroblasts Signup and view all the answers

Which of the following statements about cartilage is FALSE?

Cartilage contains nerves. Signup and view all the answers

Which type of joint is characterized by having no joint cavity and being held together by dense connective tissue?

Fibrous joint Signup and view all the answers

What is the function of the perichondrium surrounding cartilage?

Assist in the repair via chondrogenic cells Signup and view all the answers

Which type of cartilage is found in intervertebral discs and the pubic symphysis?

Fibrocartilage Signup and view all the answers

Which component of muscle connective tissue surrounds individual muscle fibers?

Endomysium Signup and view all the answers

In which type of cartilage would you primarily find chondrocytes located in lacunae?

Hyaline cartilage Signup and view all the answers

What characterizes brown adipose tissue compared to white adipose tissue?

Has more mitochondria and produces heat Signup and view all the answers

What is the role of the stratum corneum in skin health?

Provides moisture retention to prevent skin cracking Signup and view all the answers

Which antiseptic is NOT suitable for a patient with a shellfish allergy?

Povidone-iodine Signup and view all the answers

What is the primary function of sebum in the skin?

To create an acidic environment that inhibits bacterial growth Signup and view all the answers

Which cells in the dermis are involved in the inflammatory response during wound healing?

Macrophages and mast cells Signup and view all the answers

What condition is characterized by ineffective thermoregulation leading to cold extremities?

Raynaud's phenomenon Signup and view all the answers

Which statement regarding normal skin flora is true?

They vary based on body location and environmental conditions. Signup and view all the answers

What type of skin is primarily associated with eccrine glands that do not sweat for cooling?

Glabrous (hairless) skin Signup and view all the answers

Which of the following symptoms can result from nerve dysfunction in the skin?

Pruritus and numbness Signup and view all the answers

What is the primary role of osteoclasts in bone physiology?

To break down bone and release calcium Signup and view all the answers

How does calcitonin affect osteoclast activity?

It inhibits osteoclasts to decrease calcium levels Signup and view all the answers

What hormone(s) increase the activity of osteoclasts?

Vitamin D and PTH Signup and view all the answers

Which process do osteoblasts primarily stimulate?

The production of new bone Signup and view all the answers

Which of the following statements about OPG is correct?

OPG competes with RANKL for RANK on osteoblasts Signup and view all the answers

Study Notes

Exam Preparation Strategies

Focus on speaker notes from PowerPoint presentations for crucial information.
Pay attention to phrases like "that would be a good test question" as they indicate potential exam content.
Highlight major concepts; do not rely solely on presentation slides for comprehensive study.

Extracellular Matrix (ECM)

Non-cellular component of tissues providing support, strength, and shock absorption through collagen and proteoglycans.
Functions include adhesion and communication, produced predominantly by chondrocytes.

Glycoproteins and Proteoglycans

Glycoproteins are primarily proteins with added short, branched carbohydrates (glycans).
Proteoglycans are mainly composed of long, unbranched carbohydrates (glycans) attached to proteins.

Glycoprotein Synthesis

N-Linked Glycoproteins: Glycosylation begins in the endoplasmic reticulum (ER) and is completed in the Golgi apparatus.
O-Linked Glycoproteins: Glycosylation occurs exclusively in the Golgi apparatus.
Transported to cell membranes, secretory vesicles, or lysosomes.

Glycosaminoglycans (GAGs) and Proteoglycans

Proteoglycans consist of a core protein covalently bonded to GAGs, which are negatively charged heteropolysaccharide chains.
Proteoglycan aggregates, the main component of cartilage ECM, form when multiple monomers associate with hyaluronic acid.

Cartilage Structure and Function

Comprised of specialized connective tissue with cells, fibers, and ground substance without nerves, vessels, or lymphatics.
Chondroblasts synthesize the ECM; chondrocytes reside within lacunae and are critical for maintenance.
The perichondrium, made of dense irregular connective tissue, has two layers: outer fibrous and inner chondrogenic.

Joint Types

Fibrous Joints: Include sutures (skull), syndesmosis (distal ends of long bones), and gomphosis (teeth).
Cartilaginous Joints: Include synchondrosis (ribs, hyaline cartilage) and symphysis (intervertebral discs, fibrocartilage).
Synovial Joints: Have an articular cavity with hyaline cartilage, fibrous capsule, and synovial membrane producing fluid for joint lubrication.

Muscle Tissue

A motor unit consists of a lower motor neuron and its innervated skeletal muscle fibers.
Connective tissue layers associated with skeletal muscle include endomysium (individual fibers), perimysium (fascicles), and epimysium (entire muscle).

Calcium Regulation in Bone Physiology

Osteoblasts are responsible for bone formation, producing factors like RANKL and OPG.
Osteoclasts resorb bone, are stimulated by RANKL, and inhibited by calcitonin, which lowers blood calcium levels.
Vitamin D (Calcitriol) and parathyroid hormone (PTH) work to increase blood calcium, while calcitonin decreases it.

Skin and Immunity

Epidermal Cells: Langerhans cells contribute to skin immunity; dermal macrophages and mast cells are part of the inflammatory response.
Maintaining skin integrity is essential to prevent pathogen entry, aided by sebum and normal skin flora.

Thermoregulation Mechanisms

Core body temperature is maintained through mechanisms involving apocrine and eccrine glands that are under autonomic control.
Dysfunction, such as Raynaud's phenomenon, can impair blood flow to extremities in cold conditions.

Nail Anatomy

Understanding nail anatomy includes prefixes and suffixes: "onycho" (nail), "lysis" (breaking), "myco" (fungus).

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Description

This quiz covers key concepts related to the extracellular matrix, glycoproteins, and proteoglycans. You'll explore their functions, synthesis, and importance within biological tissues. Prepare to test your understanding and retention of these fundamental biological components.