Cell Organelles Flashcards
What does the nucleus contain?
Nucleolus, nucleoplasm, nuclear envelope, chromatin and nuclear pores
What’s the structure of a nucleus?
- largest organelle
- spherical
- dark patches = chromatin (made from protein and DNA)
- surrounded by the nuclear envelope
- composed of 2 membranes
- has nuclear pore - allows certain molecules through
- nucleolus inside - makes rRNA and ribosomes
- nucleoplasm - jelly like substance
What’s the function of a nucleus?
- contains genetic material in the form of DNA / chromosomes
- chromatin consists of DNA & history proteins (A histone is a protein that provides structural support for a chromosome.)
- contains instructions for making proteins by producing mRNA
- manufacture rRNA and ribosomes
What does the structure of rough Endoplasmic reticulum have
- system of membranes enclosing a fluid filled space
- has ribosomes on the outer surface
- has a large surface area
What is the function of the rough Endoplasmic reticulum?
- synthesis of proteins and glycoproteins
- provides a pathway for materials to be transported throughout the cell especially proteins
What’s the structure of the smooth Endoplasmic reticulum?
- system of membranes enclosing a fluid filled space
- large surface area
Whats the function of the smooth Endoplasmic reticulum?
- synthesis
- storage
- transport of lipids and carbohydrates
What is the structure of the Golgi apparatus?
- stack of membrane-bound flattened sacs
What is the function of the Golgi apparatus?
- modifies and packages proteins
- adds carbohydrates to proteins to form glycoproteins
- produces secretory enzymes
- forms lysosomes
What is the structure of ribosomes?
- 2 sub units (small sub unit ad large sub unit)
- contains ribosomal RNA & protein
- floats freely in the cytoplasm or attached to the membrane of rough Endoplasmic reticulum
- not surrounded by a membrane
What is the function of ribosomes?
- protein synthesis
2 types of ribosomes:
- 80S (eukaryotic cells, 25nm in diameter)
- 70S (prokaryotic cells)
What is the structure of mitochondria?
- 2 membranes separated by a fluid filled space
- inner membrane is folded to form Cristal
- central part is the matrix
What is the function of mitochondria?
Site where ATP is produced or energy is release during aerobic respiration
What is the structure of lysosomes?
- ## spherical sacs surrounded by a single membrane
What is the function of lysosomes?
- contains digestive (hydrolytic) enzymes which break down materials
- eg specialised lysosome (acrosome) in head of sperm cells to help it penetrate the egg
What is the structure of chloroplasts?
- 2 membrane separated by fluid filled space
- inner membrane is continuous with a network of thylakoids
- a stack of thylakoids is called a granum
- chlorophyll molecules are present on these membranes
What is the function of chloroplasts
- site of photosynthesis
- light energy is used to derive carbohydrate molecules from carbon dioxide
What is the structure of plasma membrane?
- made up of two layers of phospholipids back to back (aka lipids with a phosphate group attached to them)
- also has carbohydrates, glycolipid, protein and glycoprotein, cholesterol
What is the function of the plasma membrane?
- controls the entrance and exit of molecules
- selectively permeable
- protein, lipid and carbohydrate
- transported across cell membrane by diffusion, osmosis and active transport
Whats a vacuole?
Only exist in plant cells. Animal cells can contain temporary vacuoles but they are not common features
A vacuole consists of a membrane called the tonoplast, filled with cell sap; a watery solution of different substances including sugars, enzymes, salts pigments. The vacuole is important in keeping the cell firm. When the vacuole is full of sap the cell is said to be turgid.
What does protein production include?
Several organelles working together : instructions in DNA is nucleus, instructions are copied onto mRNA, mRNA moves to ribosome where protein is assembled, moves through cistmae of rough Endoplasmic reticulum and leaves via vesicle, protein transported to Golgi apparatus in vesicle, along microtubule track, protein modified & packaged protein moves in a vesicle to the cell surface membrane, protein secreted
What is the structure of centrioles?
They are self replicating organelles made up of nine bundles of microtubules and are only found in animal cells
They are short cylinders
They are not surrounded by a membrane
What is the function of the centrioles?
They help in organising cell division but aren’t always needed in the process
What is the structure of the cell wall?
- it is made of a polysaccharide cellulose and provides the cell with mechanical strength and prevents the cell from bursting when water enters
What is the function of a cell wall?
- it is made of a polysaccharide cellulose and provides the cell with mechanical strength and prevents the cell from bursting when water enters
- the cell wall of a pant cell gives it support and structure
- the cell wall doesnt seal off a cell completely from its neighbours. There are pores within the walls called plasmodesmata. These connect two cells together by their cytoplasm, enabling the exchange and transport of substances
What’s the structure of the flagella?
- long and few
- thin extensions on cell surface
- 9 sets of microtubules in a circle
- 2 central microtubules (made of flagellin)
- propeller like motion
What is the function of flagella?
- made of microtubules
- used for movement
- essential for the locomotion of individual organisms
- MOVEMENT (tail of a sperm/whole of unicellular organism)
What is the structure of the cilia ?
- short and many
- thin extensions on cell surface
- back and front beating
What is the function of the cilia?
- made of microtubules
- used for movement
- essential for the locomotion of individual organisms
- move fluid or materials past and immobile cell as well as moving a cell or group of cells
Do the cell organelle labelling activity in bio book
Pg11 and 12
