Eukaryoti Cel
The Organelles
An organelle is a small structure within a cell that carries out specific cellular functions. Most
organelles are bounded by their own lipid bilayer membrane.
SUMMARY
Organelle Function
Nucleus Contain and protect DNA; transcription;
partial assembly of ribosomes
Mitochondria Produce ATP via the Krebs cycle and
oxidative phosphorylation
Ribosomes Synthesizes proteins
RER Location of synthesis/modification of
secretory proteins
SER Detoxification and glycogen breakdown in
liver; steroid synthesis in gonads
Golgi Apparatus Modification and sorting of proteins
Lysosomes Contain acid hydrolases that digest various
substances
Peroxisomes Metabolize lipids and toxins using H2O2
The Nucleus
- Contains the genome surrounded by the nuclear envelope that separates the contents of
the nucleus into a distinct compartment (isolated from other organelles and the
cytoplasm)
The Genome
- Eukaryotic genomes are organized into linear molecules of double-stranded DNA
- The genome is split into pieces, each a separate linear DNA molecule, termed the
chromosome
- Chromosomes have a centromere near the middle to ensure that newly replicated
chromosomes are sorted properly during cell division
- Each eukaryotic chromosome also has telomeres, which maintain the ends of the linear
chromosomes during DNA replication
- Some regions of a chromosome are folded into densely packed chromatin
(heterochromatin), within which genes tend to be inaccessible and turned off
- Other regions known as euchromatin are more loosely packed and allow genes to be
activated
The Organelles
An organelle is a small structure within a cell that carries out specific cellular functions. Most
organelles are bounded by their own lipid bilayer membrane.
SUMMARY
Organelle Function
Nucleus Contain and protect DNA; transcription;
partial assembly of ribosomes
Mitochondria Produce ATP via the Krebs cycle and
oxidative phosphorylation
Ribosomes Synthesizes proteins
RER Location of synthesis/modification of
secretory proteins
SER Detoxification and glycogen breakdown in
liver; steroid synthesis in gonads
Golgi Apparatus Modification and sorting of proteins
Lysosomes Contain acid hydrolases that digest various
substances
Peroxisomes Metabolize lipids and toxins using H2O2
The Nucleus
- Contains the genome surrounded by the nuclear envelope that separates the contents of
the nucleus into a distinct compartment (isolated from other organelles and the
cytoplasm)
The Genome
- Eukaryotic genomes are organized into linear molecules of double-stranded DNA
- The genome is split into pieces, each a separate linear DNA molecule, termed the
chromosome
- Chromosomes have a centromere near the middle to ensure that newly replicated
chromosomes are sorted properly during cell division
- Each eukaryotic chromosome also has telomeres, which maintain the ends of the linear
chromosomes during DNA replication
- Some regions of a chromosome are folded into densely packed chromatin
(heterochromatin), within which genes tend to be inaccessible and turned off
- Other regions known as euchromatin are more loosely packed and allow genes to be
activated
