1.2 Flashcards
Cell theory states?
all organisms are composed of cells; the cell is the basic
unit of life.
Organisms?
can be unicellular, such as amoeba and bacteria, or multicellular such as
plants and animals.
How do new cells arise?
from pre-existing cells; specialised cells arise from undifferentiated
stem cells.
Eukaryotic cells?
have a nucleus and membrane bound organelles.
Eukaryotic cells include
plant and animal cells.
Plant cells?
have additional organelles and structures e.g. chloroplasts for photosynthesis
and cellulose cell walls for support and to maintain turgor pressure.
Nucleus?
Contains DNA which codes for or controls protein synthesis.
DNA replication occurs here.
Transcription produces mRNA
templates.
Nuclear pores?
Allow the transport of mRNA and ribosomes out of the
nucleus.
Nuclear envelope
or double
membrane?
Separates the contents of the nucleus from the cytoplasm.
Nucleolus?
Produces rRNA, tRNA and ribosomes
Chromatin?
Condenses before cell division to form chromosomes.
Rough endoplasmic
reticulum?
Packaging and storing proteins. Producing transport vesicles
which merge to form the Golgi body.
Smooth
endoplasmic
reticulum?
Produce, package and transport steroids and lipids.
Golgi body/
apparatus?
Packaging proteins for secretion from the cell. Modification
of proteins e.g. by adding carbohydrate chains to form
glycoproteins.
Producing lysosomes and digestive enzymes
(tertiary structure).
Lysosomes?
Contain powerful digestive enzymes to break down worn
out organelles or cells. Phagocytes use lysosomes to digest
engulfed bacteria.
Centrioles?
Form the spindle during cell division.
They are not present in
higher plant cells.
Mitochondria?
ATP synthesis by aerobic respiration.
Chloroplasts?
Contain photosynthetic pigments which trap light energy for
photosynthesis.
Vacuole?
Contains cell sap and stores solutes such as glucose. Swells
due to osmosis for turgidity
Ribosomes?
Protein synthesis. Primary protein structure is formed at the
ribosome.
Plasmodesmata?
Connects cells via cytoplasm filled canals, which pass through
cell walls.
Allows transport via the symplastic pathway.
Cell wall?
Mechanical strength due to the high tensile strength of
cellulose microfibrils. Transport of solutes via the apoplastic
pathway.
Cell to cell communication via the plasmodesmata