UNI Biology Organelles 💘 Flashcards
Cell membrane
Maintains internal environment
Contains what substances move in and out of the cell
Membrane enclosed semi solid substance called cytosol
Cytoplasm is made of cytoplasm and the organelles
Nucleus
Contains most dna
DNA molecules are called chromosomes when condensed
When not condensed they extend through nucleus and are called chromatin
Have one or more nucleoli which produce rna
Surrounded by nuclear envelope contains two membranes which contains pores so molecules can fit through
Chromosomes in dna associated with proteins called histones
Mitochondria
Sites of aerobic respiration where glucose is oxidized to release energy and synthesize atp
Surrounded by envelope of two membranes
Central fluid space is called matrix
Intricate folds in inner membrane are called cristae which hold enzymes in final stages of respiration
Contain their own dna
Endoplasmic reticulum
Network of membrane bound channels or lumina
Channels run through the cytosol in every cell and are called cisternae
The rough er has ribosomes attached which travel proteins through the lumen around the cell the ribosomes are not always attached
Smooth we has no ribosomes and is where lipids are synthesized
Ribosomes
Where protein synthesis occurs
Some attached to rough we some free in cytoplasm
Protein produces travels to different parts of the cell
Cell wall
Made of cellulose
Microfibrils embedded in background material (matrix) made of pectin
Orientation or cellulose microfibrils different in each layer making it strong
Fully permeable and supports cell
Gaps in cell wall are called plasmodesmata which allows material to be transported ER connects to it
Cell wall of fungi is chitin and contains nitrogen
Golgi apparatus
Flattened membrane-bound cavities
Takes enzymes and proteins from the endoplasmic reticulum and package them into membrane bound vesicles
Constantly changes appearance due to the vesicles ‘budding off’ the vesicles then transport material for fuse with cell membrane
This process is called secretion
Lysosomes
Vesicles produced by Golgi apparatus
Contain enzymes called lysozymes these enzymes can destroy by hydrolysis materials or organelles
Whole cells and tissues are destroyed due to lysosomes releasing their co tents at cell surface
Choloroplasts
Where photosynthesis takes place surrounded by two membranes forming an envelope
Contain water enzymes and stroma
Stroma has membranes which form interconnecting enclosed spaces called thylakoids
When membranes are stacked they are called grana
First stage of photosynthesis happens in grana second stage is in stroma
Have their own dna
Cell vacuole
Liquid filled space in all cells
Small vacuoles are called vesicles
Contains many different substances such as sucrose and amino acids
Can be used for storage , to isolate substances that may be harmful and help maintain cell turgidity.
Plasmids
Small loops of dna in prokaryotic cell which produce genetic codes associated with antiobiotic resistance
What is cell wall of bacteria made of
Murein
Viruses
Tiny particles of nuclei acid
Enclosed in capsid
Not living-acellular
Protein molecules on capsid attach to cell membrane and enter cell
It’s genetic material hijacks machinery cell
Copies viruses rna or dna creating many viruses
Eventually cell bursts releasing viruses
Secretory vesicles
Transport material between Golgi body and plasma membrane
Endocytic network
Vesicular system taking up (costed vesicles ) Transporting and sorting (endosomes) Or degrading (lysosomes) Macromolecules and worn out cell components
Cytoskeleton
Filaments and tubule components assembling and disassembling in a mesh network
Supports cell
Organelle distribution
Cell motion
Peroxisomes
Small vesicles containing oxidative enzymes carrying out lipid metabolism and chemical detoxification
Cell membrane structure
Phospholipid bilayer with proteins embedded
Selectively permeable small and hydrophobic can pass through
Ions and larger molecules cannot
How does membrane fluidity arise
Unsaturated fatty acids having double bond in cod or trans form
Introduces 120 degree bend in Acton chain reducing lipid lipid interactions and resulting in a lower melting point
Potential across membranes
Slightly due to sodium potassium pump 3na in 2k out via atpase
MOSTLY from k+ leak channels which open transiently allowing k+ ions to flow out down conc gradient leaving negative ions behind
Equilibrium formed no further movement of k+
Action potential of membrane value
Between -20mv and -200mv
