Organelles 4.3

Nucleus

In all eukaryotic cells

• stores cell’s DNA, of which there is 2 meters in a single human nucleus

• Directs synthesis of proteins

Nucleolus

In all eukaryotic cells

Location where ribosomes are assembled, dark stained area within nucleus, aggregates rRNA with associated proteins to assemble the ribosomal subunits that pass through pores in nuclear envelope

Nuclear envelope

In all eukaryotic cells

• double membrane system

• Contains pore that reg. Traffic in and out of

• Contiguous with ER

Pores between nucleoplasm (semi-solid fluid inside nucleus, where chromatin and nucleolus are found) and cytoplasm

Mitochondria

Found in all eukaryotic cells Location

• carries out cellular respiration produces ATP for energy

• Bounded by double membrane system

• Have their own DNA

Peroxisomes

Found in all eukaryotic cells

• Small and round enclosed by a single membrane

• carry out oxidation rxns that break down fatty and amino acids

• Detoxify poisons or toxins (increased level in liver cells)

• Produce H2O2 which is dangerous to cell but broken down within the Peroxisomes

Cytoplasm

Cells entire region between plasma membrane and nuclear envelope, comprised of organelles suspended in gel-like cytosol.

Found in prokaryotic and eukaryotic cells

Lysosomes

In animal cells

• a part of the endomembrane system

• Carry out cellular digestion

• Recycle organelles and proteins

• Can be used to destroy pathogens

• Increased number in macrophages

Centrosomes

only in animal cells

• made of two centrioles that each consist of 9 microtubule triplets

• Location from which microtubules originate

• Organizing center found near nuclei

• Unclear role in cell division

Central vacuole

• much larger than vacuoles in animals, the central vacuole is only in plants

• Vacuoles are where lysosome functions occur in plant cells

• Contain digestive enzymes

• Regulates cells water in changing environmental conditions

• Maintains turf or pressure to support structure of plant

• why plants wilt

Vesicles and vacuoles

In eukaryotic cells

Membrane-bound sacs that function in storage and transport

Vacuoles are a bit larger, but relatively similar

Vesicle membranes can fuse with membranes in the cell

Cell wall

In plants, external to plasma membrane, rigid covering that protects the cell, provides structural support & gives shape to the cell

• Primarily made up of cellulose

Chloroplasts and chlorophyll

Chloroplasts: Plant cell organelles that carry out photosynthesis have outer and inner membranes

Chlorophyll: green pigment in chloroplasts that captures light energy that drives photosynthesis reaction.