Tissues and Protein Synthesis

A comprehensive set of Q&A flashcards covering tissues, their types, functions, and the basics of protein synthesis and tissue repair.

What are the four primary tissue types?

Epithelial, Connective, Muscle, and Nervous tissues.

What is histology?

The study of tissues.

What role do genes play in inheritance and development?

Genes carry messages for the development of inherited characteristics and direct the manufacture of proteins in cells.

What are the two main functional categories of proteins mentioned?

Fibrous (structural) proteins building materials and Globular (functional) proteins that act as enzymes.

How is DNA information coded and what does a triplet code for?

DNA information is coded in a sequence of bases; a triplet codes for a specific amino acid.

What are the key differences between DNA and RNA in sugars and bases?

RNA contains ribose instead of deoxyribose and uracil (U) instead of thymine (T); RNA is typically single-stranded.

What is RNA’s essential role in protein synthesis?

RNA is essential for protein synthesis and consists of four nucleotides.

What does DNA serve as in protein production, and what must occur for expression?

DNA is a blueprint that must be interpreted; RNA is needed to carry out the steps of protein synthesis.

How do base pairs differ between DNA and RNA?

DNA pairs: C-G, G-C, A-T, T-A. RNA pairs: C-G, G-C, A-U (thymine is replaced by uracil).

What is transcription and where does it occur?

Transcription is the transfer of information from DNA to RNA in the nucleus, facilitated by RNA polymerase.

What carries the instructions for building a protein from the nucleus to the ribosome?

Messenger RNA (mRNA).

What is the role of transfer RNA (tRNA) in protein synthesis?

tRNA transfers the appropriate amino acids to the ribosome and contains anticodons that pair with mRNA codons.

What is the role of ribosomal RNA (rRNA)?

rRNA helps form the ribosomes where proteins are built.

What is the start codon and which amino acid does it typically encode?

Start codon is AUG and it codes for methionine.

Where does translation take place?

In the cytoplasm at the ribosome.

Which three types of RNA are involved in protein synthesis?

mRNA, tRNA, and rRNA.

How does transcription relate to the DNA base sequence and the mRNA sequence?

Transcription converts the DNA base sequence into a complementary mRNA sequence.

What is a polypeptide?

A chain of amino acids that forms a protein.

What is the significance of body tissues and histology?

Body tissues are groups of similar cells; histology is the study of tissues.

What are the four main tissue functions summarized (epithelial, connective, muscle, nervous)?

Epithelial covers/protects; Connective binds/supports; Muscle contracts/movement; Nervous conducts impulses.

What are the hallmark characteristics of epithelial tissue?

Cells fit closely together, one free surface, basement membrane, avascular, and regenerates easily when nourished.

How are epithelial tissues classified by layers and by cell shape?

By layers: simple (one layer) vs stratified (more than one). By shape: squamous, cuboidal, columnar.

What is simple squamous epithelium?

Single layer of flat cells; lines body cavities, lungs, and capillaries.

What is simple cuboidal epithelium?

Single layer of cube-like cells; common in glands and ducts; lines kidney tubules; ovaries.

What is simple columnar epithelium?

Single layer of tall cells; often includes goblet cells; lines digestive tract.

What is pseudostratified epithelium?

Single layer that appears multi-layered; often ciliated; functions in absorption or secretion.

What is stratified epithelium, and where is stratified squamous found?

Multiple cell layers; stratified squamous protects and is found in skin, mouth, esophagus.

What are stratified cuboidal and stratified columnar epithelia?

Rare; two layers of cuboidal cells (stratified cuboidal) and rarely stratified columnar; found in ducts of large glands.

What is transitional epithelium and where is it found?

Shape changes with stretching; lines urinary bladder.

What are endocrine and exocrine glands?

Endocrine glands are ductless and secrete hormones into the bloodstream; Exocrine glands secrete onto surfaces via ducts.

What is connective tissue and its main functions?

Found throughout the body; binds tissues together, provides support, and protects.

What is the extracellular matrix and its two main components?

Non-living material surrounding cells; composed of ground substance and fibers (collagen, elastic, reticular).

What are the main elements of the ground substance in connective tissue?

Ground substance is mostly water with adhesion proteins and polysaccharide molecules.

What are the three primary fiber types in connective tissue?

Collagen fibers, elastic fibers, and reticular fibers.

Name the major connective tissue types.

Bone, cartilage, dense connective tissue (tendons and ligaments), areolar tissue, adipose tissue, reticular tissue, and blood.

What characterizes dense connective tissue?

Main matrix is collagen fibers; cells are fibroblasts; includes tendons and ligaments.

Describe bone (osseous tissue).

Bone cells in lacunae within a hard matrix of calcium salts and abundant collagen fibers; protects and supports.

Describe cartilage and its cell type.

Cartilage is made of collagen and elastic fibers; chondrocytes produce it.

What are the three cartilage types and their key features?

Hyaline (most common; rubbery matrix with collagen), Elastic (adds elasticity; in external ear and epiglottis), Fibrocartilage (highly compressible; intervertebral discs).

What is the difference between tendons and ligaments?

Tendons connect muscle to bone; ligaments connect bone to bone.

What is areolar connective tissue?

Widely distributed, soft and pliable; contains all fiber types; can absorb excess fluid.

What is adipose tissue and its functions?

Fat-storing tissue; insulates, cushions, and stores fuel.

What is reticular connective tissue?

Delicate network forming the stroma of lymphoid organs (lymph nodes, spleen, bone marrow).

What are the three muscle tissue types and a key feature of each?

Skeletal: voluntary, attached to bone, striated, multinucleated; Cardiac: heart muscle, striated, intercalated disks, usually one nucleus; Smooth: involuntary, walls of hollow organs, spindle-shaped, non-striated.

What are neurons and their key components?

The basic units of nervous tissue; components include dendrites, a cell body (soma), an axon, and axon terminals; myelin sheath insulates.

What is the function of nervous tissue?

To send and receive nerve impulses, enabling internal communication and control.

What are the two main tissue repair options and when do they occur?

Regeneration (replacement with the same kind of tissue) and fibrosis (repair by scar tissue).

Which tissues regenerate easily and which do so poorly?

Easily: epithelial tissue, fibrous connective tissue, and bone. Poorly: skeletal muscle; cardiac and nervous tissue largely form scar tissue.

What developmental origin do epithelial, muscle, connective, and nervous tissues come from?

Epithelial from all three germ layers; Muscle and Connective from mesoderm; Nervous from ectoderm.

What happens to tissue mass and viability with aging?

There is a general decrease in mass and viability in most tissues.

What are hyperplasia and atrophy?

Hyperplasia is increase in tissue size due to increased cell number; Atrophy is decrease in tissue size due to reduced stimulation.