1.2 Cell Structure

Describe the domains of prokaryotic cells

Describe the domains of prokaryotic cells

Archaea

• found in extreme environmeents like high temps, salt concentrations, or pH

Bacteria

• traditional bacteria including most known pathogenic forms

Other is Eukarya but these cells are eukaryotic cells (have a nucleus)

List the cellular components of prokaryotic cells

cytoplasm, nucleoid, plasmids, ribosomes, cell membrane, cell wall, slime capsule, flagella, pili

Describe the function of the cytoplasm

internal fluid component of the cell

Describe the function of the nucleoid

DNA located here, DNA strand is circular and called a genophore

Describe the function of the plasmid

autonomous circular DNA molecules that may be transferred between bacteria (horizontal gene transfer)

Describe the structure of the ribosomes

complexes of RNA and protein that are responsible for polypeptide synthesis, 70s ribosomes

Describe the structure of the cell membrane

semi-permeable and selective barrier surrounding the cell

Describe the structure of the cell wall

rigid outer covering made of peptidoglycan; maintains shape and prevents bursting (lysis)

Describe the structure of the slime capsule

thick polysaccharide layer used for protection against dessication (drying out) and phagocytosis

Describe the structure of the flagella

long, slender projections containing a motor protein that enables movement

Describe the structure of the pili

hair-like extensions that enable adherence to surfaces or mediate bacterial conjugation

Label the prokaryotic cell and its organelles

Describe the process of binary fission

in prokaryotic cells, binary fission reproduces the cells

• the circular DNA is copied in response to a signal

• two DNA loops attach to membrane

• membrane elongates and pinches off in cytokinesis

List and describe the kingdoms of eukaryotes

The domain Eukarya has 4 kingdoms

• other two kingdoms are archaea and bacteria but these are separate domains

• Protista

  • unicellular organisms, multicellular organisms, no specialized tissue

• Fungi

  • cell wall of chitin, obtain nutrition via heterotrophic absorption

• Plantae

  • cell wall of cellulose, obtain nutrition via photosynthesis

• Anamalia

  • no cell wall, obtain nutrition via heterotrophic ingestion

Label the structure of a plant cell

Label the structure of an animal cell

List the organelles in both prokaryotes and eukaryotes

ribosomes, cytoskeleton, plasma membrane

Describe the structure and function of ribosomes

structure: two subunits of RNA and protein, eukaryotes have 80s and prokaryotes have 70s

function: site of polypeptide synthesis (translation)

Describe the structure and function of cytoskeleton

structure: a filamentous scaffolding within cytoplasm, fluid portion is called the cytosol, less developed in prokaryotes

function: provides internal structure, mediates intracellular transport

Describe the structure and function of plasma membrane

structure: phospholipid bilayer embedded with proteins

function: semi-permeable, selective barrier around the cell

list the organelles found in plant and animal cells but not prokaryotes

nucleus, endoplasmic reticulum, golgi apparatus, mitochondrion, peroxisome, centrosome

Describe the structure and function of the nucleus

structure: double membrane with pores, inner region called nucleolus

function: stores DNA as chromatin, site of ribosome assembly

Describe the structure and function of the Endoplasmic Reticulum

structure: membrane network that may be bare (smooth er), or studded with proteins (rough er)

function: smooth er transports lipids, rough er transports proteins

Describe the structure and function of the golgi apparatus

structure: assembly of vesicles and folded membranes near the cell membrane

function: sorts, stores, modifies, and exports secretory products

Describe the structure and function of the mitochondria

structure: double membrane, inner membrane highly folded into internal cristae

function: site of aerobic respiration (ATP production)

Describe the structure and function of the peroxisome

structure: membranous sac containing variety of catabolic enzymes

function: catalyzes breakdown of toxic substances and other metabolites

Describe the structure and function of the centrosome

structure: microtubule organizing center, contains centrioles only in animal cells

function: radiating microtubules form spindle fibers and contribute to cell division