Prokaryotic & Eukaryotic Cells Flashcards
Name the Domains of Life
Bacteria, Archaea, Eucarya
What is a Cell?
The fundamental unit of life.
The smallest structural and functional unit of an organism.
Name the types of cells
Unicellular and Multicellular
Defn Unicellular
Comprised of one cell
Defn Multicellular
Comprised of two or more cells
Defn Prokaryotics
No nucleus, typically single cells (basic)- bacteria.
Usually consists of a single compartment, the cytoplasm, enclosed by the plasma membrane.
Small in Size.
Most prokaryotes are surrounded by a cell wall.
Single circular chromosome (DNA) in the nucleoid
region.
NO membrane-bound organelles.
Unicellular
Defn Eukaryotic
Has a nucleus, much larger systems (organised)- fungi, plants, animals, protists.
Subdivided by internal membranes which create enclosed compartments (organelles) in which enzymes can operate without interference from reactions occurring in other compartments.
Larger in size.
Linear chromosomes in the nucleus that carry the genetic material.
Contains membrane-bound organelles.
Plant cells have cell walls; animal cells have cell membranes.
When was the cell discovered and by who?
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, fat cells, nerve cells, muscle cells, cells in culture, egg and sperm cells.
Binary fission
Prokaryotes (bacteria and archaea) divide
* 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.
Cell Shapes found in bacteria
COCCI- Spherical
BACILLI – rod-shaped
SPIRILLA – spiral-shaped
Asexual Reproduction (bacteria and archaea)
no new traits- direct reproduction of the same traits (identical cell).
Offspring arise from a single parent and inherit the genes of that parent.
Sexual Reproduction (bacteria)
Bacteria exchange genetic information before dividing.
Offspring have new genes and new traits.
Muscle Cells (size)
long, so that they can contract and shorten up, thereby moving body parts.
Nerve Cells (size)
long as they need to transmit nerve signals to different parts of the body.
Epithelial Cells (size)
cuboidal, columnar or squamous depending on their location in the body.
Red Blood Cells (size)
especially small because they need to get through the smallest capillaries of the circulatory system.
Chromosomes
Chromosomes house the DNA/genetic material of the organism in both prokaryotes and eukaryotes
Chromosomes in Eukaryotes
found in an organelle called the nucleus, which bound by a double membrane
Chromosomes in Prokaryotes
a double stranded circular structure not enclosed by a membrane. Found in the nucleoid region.
Types of Eukaryotic Cell Division
Somatic and Reproductive
Somatic Cell Division
occurs by mitosis and cytokinesis:
- growth, development, repair.
- asexual reproduction
Reproductive Cell Division (Eukaryotic)
occurs via meiosis:
- for reproduction.
- yields cells with half the DNA content.
- yields gametes (e.g. egg and sperm) or spores.
Cytoplasm (Eukaryotic)
occupies the space between the nucleus and plasma/cell membrane
Cell Membrane
surrounds the cytoplasm
Cytoplasm (Prokaryotic)
occupies in the interior of the cell
Ribosomes
Builds proteins
