PHSC1212 Biochemistry - Lecture 2 Nonmembranous Organelles

somatic and sex

two types of cells

sperm and oocyte

reproductive/sex/germ cells

somatic cells

all cells that make up the body's tissues and organs, cells besides sex cells

meiosis

How are sex cells produced?

mitosis

How are somatic cells produced?

plasma membrane

outer membrane of cells; separates cytoplasm from extracellular fluid

phospholipid bilayer with many protein and carbohydrate components

plasma membrane composition

selectively permeable

key feature of the plasma membrane

receive and transmit signals from extracellular environment

In addition to helping with transport, what can the cell membrane also do?

cytoplasm

all the materials inside the cell, but outside the nucleus

cytosol and organelles

What is the cytoplasm made up of?

cytosol

intracellular fluid around organelles

dissolved materials, high potassium, low sodium, high protein, negative charge

characteristics of the cytosol

nutrients, ions, proteins, waste products

What kind of dissolved materials are in the cytosol?

nonmembranous and membranous

two types of organelles

cytoskeleton, microvilli, centrioles, cilia, ribosomes, proteasomes

nonmembranous organelles

endoplasmic reticulum, golgi apparatus, lysosomes, peroxisomes, mitochondria, nucleus

membranous organelles

cytoskeleton

structural proteins that give the cell its shape and strength

structural proteins

The cytoskeleton is made up of ___________________________ that give the cell its shape and strength

anchor or move organelles and organize metabolic reactions

What does the cytoskeleton serve to do?

proteins and mRNA

What might attach to the cytoskeleton?

microfilaments, intermediate filaments, microtubules

three components of the cytoskeleton

microfilaments

filaments that aid in mechanical stability, cell motility and shape changes, and cytokinesis; protein actin

actin

protein of microfilaments

mechanical stability, cell motility and shape changes, cytokinesis

microfilament functions

anchor cytoskeleton to integral plasma membrane proteins

How do microfilaments give the cell additional mechanical strength?

more gelatinous

cytosol consistency when more microfilaments

more fluid

cytosol consistency when fewer microfilaments

intermediate filaments

component of cytoskeleton that significantly strengthens the cell and maintains shape under mechanical stress

keratins, lamins, desmins, neurofilaments

four proteins that could make up intermediate filaments depending on the cell type

keratin

intermediate filament protein found in skin, hair, and fingernails

lamins

intermediate filament protein found in the nucleus and reinforce the nuclear envelope

desmins

intermediate filament protein found in muscle cells

neurofilaments

intermediate filaments found in neurons

significantly strengthen cell, maintain shape under mechanical stress, stabilize cell position

functions of intermediate filaments

microtubules

largest component of the cytoskeleton

tubulin

protein that makes up microtubules

large, hollow tubes

What is the structure of microtubules like?

provide primary architectural framework of cell, determine overall shape and position of organelles, and move vesicles and organelles within the cell

What do microtubules do?

centrosome

Where do microtubules originate?

motor proteins kinesin and dynein

How do microtubules move vesicles and organelles?

centrioles and cilia

What are made up by microtubules?

form mitotic spindles

How are microtubules involved in cell division?

microvilli

small finger-like projections on surface of certain cells

microfilaments covered by cell's plasma membrane

composition of microvilli including the covering

cytoskeleton via microfilaments

What do microvilli attach to?

increase surface area for absorption

What is the function of microvilli?

non motile

microvilli and primary cilia mobility

within centrosome, near nucleus

Where are centrioles located?

nine sets of triplet microtubules

centriole composition

organize mitotic spindle formation during cell division

What do centrioles do?

cilia

small, hair-like motile projections of plasma membrane

microtubules in 9+2 array

cilia composition (motile)

primary and motile

two types of cilia

move fluids over cell surface

motile cilia function

environment sensor and cell signaling

primary cilia functions

ribosome

site of protein synthesis and massive complex of RNA and proteins

free and fixed

two types of ribosomes

cytoplasm, endoplasmic reticulum

free ribosomes are in the ____________ and fixed ribosomes are attached to the _____________________________

use inside the cell

What do free ribosomes manufacture proteins for?

secretion, membrane embedding, or lysosomes

What do fixed ribosomes manufacture proteins for?

large and small subunits

ribosome composition

specialized proteins and rRNA

ribosomal subunit composition

ribosomal RNA

What is the ribosome structure largely composed of?

binding of mRNA to small subunit

How is protein synthesis initiated?

proteasome

hollow barrel shaped structure composed of proteins and containing proteases

proteases

protein-digesting enzymes found in proteasome

disassemble damaged or abnormal proteins into smaller peptides and amino acids

proteasome function

cytoplasmic enzymes

attach a tag to damaged proteins to signal the proteosome to degrade the tagged protein

ubiquitin

"tag" attached to damaged proteins by cytoplasmic enzymes to signal proteasomes to degrade