Cell Structure Flashcards
Cell Theory
a scientific theory which describes the properties of cells. These cells are the basic unit of structure in all organisms and also the basic unit of reproduction. … Cell theory was eventually formulated in 1839. This is usually credited to Matthias Schleiden and Theodor Schwann.
Plasma membrane
the boundary between the cell and its environment. It regulates what enters and exits the cell.
Organelles
Found only in eukaryotic cells and are absent from the cells of prokaryotes such as bacteria. The nucleus, the mitochondrion, the chloroplast, the Golgi apparatus, the lysosome, and the endoplasmic reticulum are all examples of organelles.
Cytoplasm
thick solution that fills each cell and is enclosed by the cell membrane.
Cytosol
liquid matrix around the organelles. Part of the Cytoplasm.
Cytoskeleton
present in all cells of all domains of life (archaea, bacteria, eukaryotes).network of protein filaments and tubules in the cytoplasm of many living cells, giving them shape and coherence.
Nucleus
a membrane bound structure that contains the cell’s hereditary information and controls the cell’s growth and reproduction
Ribosomes
particle consisting of RNA and associated proteins, found in large numbers in the cytoplasm of living cells. They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins.
Cell wall
structural layer that surrounds some types of cells, situated outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides cells with both structural support and protection, and also acts as a filtering mechanism.
Nuclear envelope
phospholipid bilayer membrane which surrounds the genetic material and nucleolus in eukaryotic cells, consists of two lipid bilayers—the inner nuclear membrane, and the outer nuclear membrane.
Chromatin
Efficiently package DNA into a small volume to fit into the nucleus of a cell and protect the DNA structure and sequence
Chromosomes
threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.
Nucleoli
a small dense spherical structure in the nucleus of a cell during interphase.
Endomembrane system
endoplasmic reticulum Golgi apparatus vesicles cell membrane nuclear envelope lysosomes endosomes
Endoplasmic reticulum
a type of organelle in the eukaryotic cells that forms an interconnected network of flattened, membrane-enclosed sacs or tube-like structures known as cisternae.
ER lumen
area enclosed by the endoplasmic reticulum membrane, an extensive network of membrane tubules, vesicles and flattened cisternae (sac-like structures) found throughout the eukaryotic cell, especially those responsible for the production of hormones and other secretory
Golgi complex
packages proteins into membrane-bound vesicles inside the cell before the vesicles are sent to their destination.
Secretory vesicles
a vesicle is a small structure within a cell, consisting of fluid enclosed by a lipid bilayer.
Exocytosis
form of active transport in which a cell transports molecules (such as proteins) out of the cell (exo- + cytosis) by expelling them in an energy-using process.
Secretion
movement of material from one point to another, e.g. secreted chemical substance from a cell or gland.
Endocytosis
form of active transport in which a cell transports molecules (such as proteins) into the cell (endo- + cytosis) by engulfing them in an energy-using process.
Endocytic vesicle
Molecules are delivered from the plasma membrane to early endosomes in endocytic vesicles.
Lysosome
membrane-bounded organelle found in most animal cells. They are spherical vesicles which contain hydrolytic enzymes that can break down virtually all kinds of biomolecules.
Phagocytosis
specific form of endocytosis involving the vascular internalization of solids such as bacteria by an organism, and is therefore distinct from other forms of endocytosis such as the vesicular internalization of various liquids (taking it in)
Mitochondria
a double membrane-bound organelle found in all eukaryotic organisms, although some cells in some organisms may lack them (e.g. red blood cells). The ATP is produced in the mitochondria using energy stored in food.
Mitochondrial matrix
the space within the inner membrane
Inner and outer mitochondrial
membranes
The outer mitochondrial membrane fully surrounds the inner membrane, with a small intermembrane space in between. The outer membrane has many protein-based pores that are big enough to allow the passage of ions and molecules as large as a small protein.
Peroxisomes
major function of the peroxisome is the breakdown of very long chain fatty acids through beta-oxidation.
Chloroplasts
main role is to conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight and converts it and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water.
Vacuoles
enclosed compartments which are filled with water containing inorganic and organic molecules including enzymes in solution, though in certain cases they may contain solids which have been engulfed
Make a table of all the membrane-bound organelles found in eukaryotes. For each, describe
its overall structure and describe one major function.
?
Explain why membrane-bound organelles are useful to eukaryotes
embranous organelles help to compartmentalize the cell so that each reaction in the organelle is separate from those of other organelles and have a variety of organelles that carry out different functions simultaneously, thereby increasing efficiency. Membranes also offer protection. In addition, the organelles can also be in logical proximity to others that have related functions. For example, organelles producing proteins within the cell can be near other organelles involved in transporting the proteins out of the cell. Nuclear membranes around DNA allow for the regulation of different materials into and out of the nucleus and protection of DNA material.
What major cell structures are found in plants but not animals?
Plant cells have a cell wall, chloroplasts and other specialized plastids, and a large central vacuole, which are not found within animal cells.
Describe what different organelles make up the endomembrane system and what it’s two
main functions are.
endomembrane system does not include the membranes of chloroplasts ( photosynthesis) or mitochondria ( ATP is produce & energy stored in food)
Cite the evidence for the endosymbiotic theory of mitochondria and chloroplasts.
describes how a large host cell and ingested bacteria could easily become dependent on one another for survival, resulting in a permanent relationship. Over millions of years of evolution, mitochondria and chloroplasts have become more specialized and today they cannot live outside the cell.
Dinoflagellates are single-celled eukaryotes that make up a large portion of the plankton in
oceans and fresh water. Population explosions of dinoflagellates cause what are known as red
tides. Some dinoflagellates are photosynthetic and contain chloroplasts. However, these
chloroplasts are unique because they have 3 envelope membranes, not the 2 envelope
membranes found in plants. What is the source of the extra membrane around dinoflagellate
chloroplasts? Why is this referred to as a secondary endosymbiosis?
Secondary Endosymbiosis occurs when the host cell in primary Endosymbiosis is itself engulfed by another cell. This process is illustrated in the diagram above. A green algae, which descended from the product of primary Endosymbiosis, is engulfed by a larger heterotrophic cell. The green algae then becomes a red algae inside the host cell by losing the nucleus and mitochondria that had been present before the algae engaged in primary Endosymbiosis. The result is a double membrane bound organelle containing all the structures necessary for photosynthesis. Over time these red algae evolved to become the plastids known as chloroplasts.
