Nucleus
-double membrane
-disappears during cell division
- contains DNA (genetic code to produce
another cell) and RNA (production,
nucleoplasm, nucleolus)
- directs cell activity by expressing genes
from DNA
Nucleoplasm
-thick, jelly like liquid
- stains darker than cytoplasm
- nuclear envelope contains
nucleoplasm
- contains amino acids, ribose sugars and
nitrogenous bases to produce RNA and to
copy DNA
-contains chromatin
Nucleolus
- dark stained spherical
structure within nucleoplasm
- involved in making RNA (r-RNA is
ribosomal RNA used in forming ribosomes)
Cytoplasm
-fluid inside cell membrane and
outside nucleus
-colourless
-cell activities take place here
- absorbed nutrients and wastes are
transported and stored
- provides constant environment for cells
Mitochondria
-oval (bean) shaped
-smooth outerlining
- inner membrane made of finger
like projections called cristae
-more in active cells
- has its own DNA
-produce energy through cellular
respiration which is stored as ATP
(adenosine triphosphate)
(glucose and oxygen required for energy
production)
Lysosome
-bound by single membrane
-formed by Golgi Apparatus
-only in animals
-variety of enzymes that breakdown large
molecules and cell parts in cytoplasm
-breakdown food molecules brought into
cell
-WBC –engulf bacteria –enzymes destroy it
-can destroy cell (apoptosis)
Rough
Endoplasmic
Reticulum (RER)
-series of canals/parallel
membranes found throughout
cell
-many ribosomes are present
-transport materials throughout the
cytoplasm (proteins, lipids, glycoproteins)
*prevalent in cells specializing in secreting
proteins
Smooth
Endoplasmic
Reticulum
(SER)
-series of canals/parallel
membranes found throughout
cell
-NO ribosomes are present
-fats (lipids) are synthesized here
-*prevalent in cells developing seeds and
animal cells that secrete steroid hormones
Ribosome
-made up of RNA and protein
- 20 nm in length
-among smallest organelles
-protein synthesis
- organizes and sequences amino acids to
form functional and structural proteins
-instructions from RNA tell which proteins
to produce
Vacuole
-clear, fluid – filled membrane
bound sac (most prominent in
plant cells)
-storage areas for water, food, minerals
and wastes
-contents exert pressure to keep plant cell
walls rigid (turgor pressure)
Golgi Apparatus
-like a stack of flattened
balloons – membranous sac piled
on top of each other
-stores, modifies and packages proteins
from RER with fats
-membrane-bound structures pinch off at
end to produce small protein-filled sacs
called vesicles which are used for
transport (eg. hormones,
neurotransmitters)
Plastids
-membrane-bound organelle
*found in plants only
-chemical factories and storehouses for
food and colour pigment
Chloroplasts
-plastid which contains
chlorophyll
Has its own DNA and ribosomes
*found in plants only
-photosynthesis occurs here
(carbon dioxide + water
sugar and oxygen)
Cell Wall
-made of cellulose
*found in plants only
-protection, support
-primary (single cell wall)
-secondary (double cell wall) – extra
protection and support
Cell Membrane
-protein, double layer of lipid
-receptor site
-holds content of cell in place
-regulates movement in and out of cell
-entry of materials affect cell activity
-SELECTIVELY PERMEABLE
*more info to follow
Liposomes
-double layered spheres
-size of a cell
-made of lipids
-like cell membrane, fuse with cell
membrane and deliver contents to cell’s
interior
-used for drug delivery (eg. cancer fighting
drugs to target tumours)
Nuclear
Membrane
-membrane found around the
nucleus
-controls what enters and exits the
nucleus ie. RNA, copies of DNA
-dissolves during mitosis and meiosis (cell
division)
Flagella
(singular:
flagellum)
-whip like protein
-may have one or many
-found in animal cells
-eg. sperm cells
-help cell move – uses contractile proteins
to spin in a corkscrew motion (propeller
from boat)
Cilia
(singular: cilium)
-short, hair like structures
-uses contractile proteins for movement in
a “coordinated” fashion
-used for –locomotion
-to create fluid currents to
move materials (eg. lung cells)
Microfilaments
-threadlike (pipelike) structures
-made of protein
-found in cytoplasm
-provide shape and movement for cells
(muscle contraction, gliding, cytokinesis)
Microtubules
-tubelike structures
-made or proteins
-found in spindle fibres, cilia and
flagella
-transport materials throughout cytoplasm
Chromatin
-DNA molecules and associated
proteins
(chromosomes are long and thin)
-unravelled DNA available to be copied into
RNA
Centromere
-found between sister
chromatids
-structure that holds chromatids together
Sister
chromatids
-a chromosome and its duplicate
attached to one another by a
centromere
-remain attached until separated during
mitosis
Centrioles
-formed by a bundle of nine
microtubules
-occur in pairs at right angles to
one another
-found only in animal cells
-active during cell division
-help to redistribute chromosomes (use
spindle fibres)