prokaryotic & Eukaryotic cells Flashcards
what are the three domains of life?
Domain Archaea
Domain Bacteria
Domain Eucarya
what is a cell?
A cell is the fundamental unit of life.
The smallest structural and functional unit of an organism.
unicellular
comprised of ONE cell
multicellular
Comprised of TWO or MORE cells
discovery of the cell
Robert Hooke - 1665
CELL THEORY
- All organisms are composed of one or more cells!
- The cell is the basic unit of structure and organisation in organisms.
- All cells come from pre-existing cells.
examples of cells
Red blood cells
Nerve cells
Fat cells
Muscle cells
Cells in culture
Egg & Sperm cells
prokaryotes
no nucleus (bacteria)
Eukaryotes
nucleus (fungi, plants, animals, protists)
A Prokaryotic cell
usually consists of a single compartment, the cytoplasm, enclosed by the plasma membrane.
A Eukaryotic cell
is subdivided by internal membranes which create enclosed compartments (organelles) in which enzymes can operate without interference from reactions occurring in other compartments.
All cells have…….
PLASMA MEMBRANE = traffic regulation
CYTOPLASM = suspend cellular components
CHROMOSOMES = contain genes
RIBOSOMES = build proteins
prokaryotic cell features:
= small in size.
= cytoplasm occupies in the interior of the cell.
= cell membrane surrounds the cytoplasm.
= surrounded by a cell wall.
= single circular chromosome in the nucleoid region.
= NO membrane bound organelles.
= unicellular but can clump to form aggregates.
cells shapes in Bacteria:
COCCI = spherical
BACILLI = rod-shaped
SPIRILLA = spiral-shaped
what is the name of prokaryotic cell division?
Binary Fission
Binary Fission
This begins at the ORIGIN OF REPLICATION (ORI) and occurs in both directions. The two copies of the DNA molecule are partitioned to either side of the cell. A SEPTUM forms to divide the two new cells. This is a form of ASEXUAL REPRODUCTION.
what is asexual reproduction?
Offspring arise from a single parent and inherit the genes of that parent.
Bacterial Conjugation
some bacteria reproduce sexually.
Sexual reproduction: bacteria exchange genetic information before dividing.
Offspring have new genes and new traits.
The Eukaryotic cell features:
= larger in size compared to prokaryotes.
= cytoplasm occupies the space between the nucleus and plasma/cell membrane.
= Linear chromosomes in the nucleus that carry genetic material.
= cell membrane surrounds the cytoplasm.
= contains membrane-bound organelles.
= Plant cells have cell walls; animal cells have cell membranes.
MUSCLE CELLS:
are long, so that they can contract and shorten up, thereby moving body parts.
NERVE CELLS:
are also long as they need to transmit nerve signals to different parts of the body.
EPITHELIAL CELLS:
are cuboidal, columnar or squamous depending on their location in the body.
RED BLOOD CELLS:
are especially small because they need to get through the smallest capillaries of the circulatory system.
No ‘nucleus’ versus ‘true nucleus’
Both prokaryotes and eukaryotes have genetic material in the form of chromosomes.
In eukaryotes, chromosomes are found in an organelle called the nucleus, which bound by a double membrane.
In prokaryotes the chromosome is a double stranded circular structure not enclosed by a membrane. Found in the nucleoid region.
chromosomes
house the DNA/genetic material of the organism
Eukaryotic Cell Division (complex)
SOMATIC
REPRODUCTIVE
Somatic cell division occurs by:
mitosis & cytokinesis
mitosis & cytokinesis:
growth, development, repair
asexual reproduction
Production of reproductive cells occurs via:
meiosis
meiosis:
for reproduction
yields cells with half the DNA content
yields gametes (e.g. egg and sperm) or spores
