organelles Flashcards
(28 cards)
prokaryotic cells
- oldest cell type
-small and simple
-lack nucleus
-lack membrane -bound organelles
-single celled
-single circular chromosomes (DNA) and multiple small simple plasmids(genetic material)
-simple cytoskeleton
-Prokaryotic organisms are unicellular
-The plasma membrane is surrounded by an outer cell wall.
-Many prokaryotes have flagella to enable them to move.
eukaryotic cells
-Eukaryotic cells are relatively large and more complex
- They have membrane-bound organelles such as a nucleus and mitochondria
-multicellular or single celled
multiple linear chromosomes (DNA)
-not all have a cell wall only plants and fungi
-complex cytoskeleton
Cytosol
is the aqueous fluid (dissolved salts and nutrients) that surrounds the organelles inside the cell
Cytoplasm
-Clear fluid within cell plus all organelles
The liquid (dissolved substances) around the organelles is called the cytosol
-Moves materials throughout the cell
-Cytoplasmic streaming: The movement of the fluid substance
Plasma Membrane
-Outer boundary of cell
-Protects the cell
-Composed of lipid molecules that are interspersed with tiny protein channels.
-Controls what enters and leaves the cell.
Cell Wall
-Only found in plant cells
-Adds protection and support
-Made of cellulose - a complex carbohydrate
-Allows water and dissolved substances to pass through.
Mitochondria
-Energy producers
-Site of cellular respiration- series of chemical reactions to make energy (ATP)
-Many mitochondria in muscle cells
ribosomes
-Makes proteins in the cell
-May be free in cytoplasm or attached to endoplasmic reticulum (ER)
-All cells must produce protein
Nucleus
-Controls most activities in the cell
-Contains all genetic information in the form of Deoxyribonucleic acid (DNA).
Endoplasmic Reticulum
-Series of folded membranes that form sacs or tubes
-Rough ER has ribosomes attached
-Proteins made by the ribosomes are packaged and transported by the ER
-Smooth ER has no ribosomes attached.
-Smooth ER synthesises lipids and assists in manufacturing of plasma membrane.
Golgi Bodies
-Also called Golgi apparatus or Golgi complex
- used for storing/ packaging and modifies protein
-Cells that make saliva or mucus have many Golgi bodies
-Site of modification, sorting, and secretion of lipids and proteins
Lysosomes
-Formed by the Golgi bodies
-Contain digestive enzymes to digest unwanted particles
-Help white blood cells to destroy bacteria
-Sometimes lysosomes may destroy the entire cell. Lysosome membrane ruptures, releasing enzymes, which then digest the contents of the cell: apoptosis (cell suicide).
-break down non-functional organelles
Plastids
-Organelles that contain coloured pigments
Chloroplasts
-Only found in plants/ algae
-Contain the pigment chlorophyll
Carry out the process called photosynthesis
Cytoskeleton
3D structure in the cytoplasm that provides cell shape
Vacuoles
-Store food, water, or waste materials
-Plant cells have large vacuoles
-Vacuoles are able to expand, taking up 50-90% of the volume of the cell.
Why are cells so small?
- Cells grow to size they need to perform their specific function.
- Cells supply their entire cytoplasm with materials that enter by the plasma (cell) membrane.
-Therefore cells need a large surface area and a smaller volume to adequately supply the cytoplasm.
Cell Theory
-All organisms are composed of cells (and cell products)
-All cells come from pre-existing cells
-The cell is the smallest living organisational unit
All living things share the following attributes, remembered through the acronym MRS GREND.
M — movement: have some level of self-powered movement
R — respiration: the conversion of carbohydrates to a usable energy form (ATP)
S — sensitivity to stimuli: the response of an organism to its environment (e.g. plants responding to light, animals responding to external temperatures by sweating, shivering)
G — growth: an irreversible change in mass
R — reproduction: production of offspring, passing attributes from one generation to the next
E — excretion of wastes: produce wastes, such as dead cells or urine, that need to be removed
N — nutrition: intake of food or nutrients
D — DNA: the molecule that codes for the production of proteins
For life to survive in a place, there are a set of conditions that need to be met:
-energy source
-liquid water
-building blocks to make necessary molecules
-stable environment
what are cells
Cells are the basic structural and functional units of life.
what if the cell increases in size?
it may struggle to support the higher volume, slowing nutrient absorption and waste expulsion
why is cell size limited?
it is to ensure the exchange of resources and waste occurs quickly enough for the survival of the cell
what makes a plant cell different
- have a cell wall
-big vacuole
-contains plastids
what makes a animal cell different
- lack cell wall
- small vacuoles
