Human Anatomy Cells and Tissues

Transcription

transfer the genetic message from DNA to RNA

Translation

Assembly of amino acids according to the genetic information carried by mRNA

mRNA (messenger RNA)

Carries the genetic code from DNA to the ribosomes, essentially providing the blueprint for protein synthesis.

tRNA (transfer RNA)

Transports specific amino acids to the ribosomes during protein translation, matching the amino acid to the correct codon on the mRNA. 

rRNA (ribosomal RNA)

Forms the structural core of the ribosomes, which are the cellular machinery responsible for protein synthesis. 

Simple diffusion

• An unassisted process

• Solutes are lipid-soluble or small enough to pass through membrane pores

Diffusion

when the molecule moves from HIGH concentration to LOW

• down a concentration gradient

• size of molecule and temperature can affect the speed of diffusion)

osmosis

• simple diffusion of water across a selectively permeable membrane

  • Highly polar water molecules easily cross the plasma membrane through aquaporins

  • Water moves down its concentration gradient

Exocytosis

• Mechanism cells use to actively secrete hormones, mucus, and other products

• Material is carried in a membranous sac called a vesicle that migrates to and combines with the plasma membrane

• Contents of vesicle are emptied to the outside

•  EXPELS material into the extracellular space

Endocytosis

• Docking proteins on the vesicles recognize plasma membrane proteins and bind with them

• Membranes corkscrew and fuse together

• ENGULFS extracellular materials

phagocytosis

 disposes of dead body cells and bacteria

• MACROPHAGE is one of the white blood cell “eater”

Pinocytosis

the cell “gulps” extracellular fluid containing dissolved fat or proteins

• The cell “drinks”

Facilitated diffusion

transports lipids insoluble and large substances

• (glucose is transported through this diffusion)

• Protein membrane channels or protein molecules that act as carriers are used

Active transport

(energy is required) Amino acids, some sugars, and ions are transported by protein carriers known as solute pumps.

• ATP energizes solute pumps

• the cell provides the metabolic energy to drive the transport process

Mitosis

the division of a nucleus resulting into two daughter nuclei

Cytokinesis

• begins near the completion of the mitosis phase

• the division of a cytoplasm

• resulting in two daughter cells

hypertrophy

• refers to the increased size of cells which increases in the size of the affected organ

• THERE IS NO NEW CELLS- JUST LARGER CELLS

a tissue or organ may occur when tissue is strongly stimulated or irritated

hyperplasia

• refers to the increase in the number of cells in an organ or tissue

• THERE IS NEW CELLS

the enlargement of an organ or tissue caused by an increase in the reproduction rate of its cells, often as an initial stage in the development of cancer.

protein carrier

• facilitates passive and active transport

• transports substances slower

• carries amino acids, sugar, and nucleosides

• may use energy depending on the protein

• synthesized in the free ribosomes in the cytoplasm

protein channel

• doesn’t need energy to transport

• facilitates passive transport

• carries ions and water molecules

• transports faster

• synthesized in the rough ER

Osteocyte

a cell that lies within the substance of fully formed bone; it helps regulate the formation of new bones (remodeling and repair)

• BONE CELLS

Chondrocyte

the only specialized cell type found in the cartilage tissue.

atrophy

DECREASE IN SIZE

•  a tissue or organ occurs when the organ is no longer stimulated normally

Neoplasm

A NEW AND ABNORMAL GROWTH OF TISSUE

• both benign and cancerous, represent abnormal cell masses in which normal controls on cell division are not working

nucleus

Stores DNA, controls cell activities, and directs protein synthesis. 

Mitochondria

• the powerhouse of the cells

• Generates energy in the form of ATP through cellular respiration.

• wall consists of a double membrane with cristae on the inner membrane

ribosomes

• made of protein and RNA

• sites of protein synthesis in a cell

• found free in the cytoplasm or rough ER

• Synthesize proteins based on instructions from mRNA

Endoplasmic reticulum (ER)

• Fluid-filled tunnels (or canals) that carry substances within the cell

• continuous with the nuclear membrane

Smooth ER

• synthesize lipids

• detox drugs and pesticides

• lacks ribosomes

• functions in lipid metabolism

Rough ER

• studded with ribosomes

• synthesizes proteins

• Transport vesicles move proteins within cell

• Abundant in cells that make and export proteins

golgi apparatus

• Appears as a stack of flattened membranes associated with tiny vesicles

• Modifies and packages proteins arriving from the rough E R via transport vesicles

• Produces different types of packages

• Packages, modifies, and sorts proteins for secretion.

lysosomes

• Membranous “bags” that contain digestive enzymes

• Enzymes can digest worn-out or nonusable cell structures

• House phagocytes that dispose of bacteria and cell debris

• Digest waste materials and cellular debris using enzymes. 

peroxisome

• Membranous sacs of oxidase enzymes

  • Detoxify harmful substances such as alcohol and formaldehyde

  • Break down free radicals (highly reactive chemicals)

  • Free radicals are converted to hydrogen peroxide and then to water

endocrine glands

Ductless; secretions (hormones) diffuse into blood

• Examples include thyroid, adrenals, and pituitary

exocrine glands

Secretions empty through ducts to the epithelial surface

• Include sweat and oil glands, liver, and pancreas (both internal and external)

nucleolus

located at the center of nucleus

• MAKES RIBOSOMES

chromatin

located in the nucleus

• MAKES DNA

inclusions

located in the cytoplasm

• MAKES PIGMENTS

Plasma membrane

function: confines cell contents; regulates entry and exit of materials

microvilli

function; increase the membrane surface area

centrioles

function: direction formation of the mitotic spindle