chapter 7: basic cell properties and processes

golgi complex

packages for exocytosis, produces lysosomes

can modify protein molecules → glycoproteins

remove insulin in a polypeptide chain

lysosomes

usable material out to ICF, indigestable is taken inside and broken down for exocytosis to release it

inclusions

metabolically inert substances

non-membrane bound storage deposits for nutrients or waste products (ex: melanin)

(ex: residual bodies of lysosomes- neutralize acids and enzymes)

apoptosis

genetic material becomes debris for phagocytosis (removes overproduction)

function of tissue stem cells

replace worn/damaged cells (as cells decrease in function over time)

extracellular fluid

transports and dissolves

intracellular fluid

fills spaces and acts as a barrier

common element is hyaluronic acid (biologic), which resists compression by cushioning with water

desmosomes

form inercellular junctions. allows receptors on each cell surface to bind to each other, increasing development

also allows for cellular migration to injured area (for mitosis)

appears disc shaped

hemidesmosomes

attaches the cell to a noncellular surface (epithelium to connective tissue) (ex: allows gums to secure to teeth)

only has tonofilaments from the cellular side

exocytosis

fusion of a vesicle membrane with the cell membrane, expulsion of contained material

endocytosis

invagination of the cell membrane

phagocytosis- engulf then digest solid waste and foreign material (enzymatic breakdown)

chromatin

DNA that condenses into chromosomes

centromere

clear restricted area near the middle

chromatids

chromosomes form into this

nuclear pores

pierce nuclear envelope

act as avenues of communication between inner nucleoplasm and outer ICF

cytoskeleton

microfilaments and tubules

projections like cilia and flagella

how does the nucleus work on DNA and RNA?

DNA is stored in the nucleus

nucleus transcribes DNA into RNA with mRNA and tRNA

what occurs during both cell division and interphase?

cell division- growth and repair

interphase- when DNA is replicated

what are the four phases of cell division and what occurs during each phase?

• Prophase – Chromatin condenses into chromosomes; spindle fibers form; nuclear envelope begins breaking down.

• Metaphase – Chromosomes line up at the cell’s equator; spindle fibers attach to centromeres.

• Anaphase – Sister chromatids separate and are pulled to opposite poles of the cell.

• Telophase – Chromosomes de-condense back into chromatin; nuclear envelopes reform; spindle breaks down. (Cytokinesis usually follows, splitting the cytoplasm.)

what is the purpose of intercellular junctions?

attachment devices are used to facilitate exchange/migration and communication

(ex: stem cells migrate to injured areas)

what is the cell membrane and what does it consist of?

“gatekeeper”

bilayer of mostly phospholipids and proteins (serve as structural reinforcements and receptors)

what is the relationship between chromatin, chromosomes, and chromatids?

chromatin is loose and threadlike, condenses into tightly-packed rodlike chromosomes

chromatids are the two identical halves of a duplicated chromosome

centrosome

dense and oval-shaped organelle that contains the centrioles

always located near the nucleus, forms the mitotic spindle apparatus during cell division