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Nucleus: The 'brain' of the cell. It contains DNA. It is important to note that DNA codes for PROTEIN. Proteins make up enzymes (amylase), receptors (ACE-2), as well as structural proteins (hair-keratin).
Structure: The nucleus contains small holes in it called nuclear pores. This allows for mRNA to move from the nucleus to the ribosome during transcription. The nucleus also has an inner region known as the nucleolus, where the DNA is highly coiled and condensed.
Transcription: Where a copy of DNA, known as mRNA, is made in the nucleus and moves out of the nuclear pore.
Translation: Where this mRNA strand is read by a ribosome to make a protein.
DIAGRAM OF A PLANT CELL
Cytoplasm
Ribosome
Cell membrane
Vacuole
Mitochondrion
Chloroplast
Endoplasmic Reticulum
Nucleus
Cell Wall
Ribosome: Ribosomes are small organelles made up of protein and RNA. Their function is to make proteins. They do so in a process called translation, where the mRNA copied from the nucleus is fed into the ribosome, and the ribosome attaches amino acids together to form a polypeptide (many amino acids joined by peptide bonds).
Reading: Ribosomes read the mRNA code in sets of three letters (or bases) at a time. For each three letters, a specific amino acid is brought to the growing polypeptide chain.
Termination: Ribosomes stop synthesising a polypeptide from an mRNA chain when they reach a STOP codon, which is a specific three letter code that stimulates the ribosome to stop translation.
Mitochondrion: The infamous 'powerhouse of the cell', the mitochondrion is an ATP-generating organelle and also the site of aerobic respiration.
ATP: A unit of energy 'currency' in the biological world. ATP can be broken down to release the chemical energy stored in its bonds. Processes such as active transport are driven by breaking down ATP, for example.
Aerobic respiration: The process used to make ATP by breaking down substrates such as carbohydrates. This occurs in the mitochondria.
One = Mitochondrion
Two = Mitochondria
Plasma membrane: The partially permeable boundary to the cell. It is referred to as a phospholipid bilayer, because it is composed of a layer of lipids two-units thick. The plasma membrane controls what goes into and out of the cell. It also has embedded in it proteins which acts as receptors or transport proteins.
Vesicle membrane: Vesicles are small organelles which contain a given material. They are small spheres of membranes which help carry things to the plasma membrane (exocytosis) and from the plasma membrane (endocytosis).
Golgi membrane: The Golgi is a stack of membranes that are highly folded. This allows the Golgi to package things such as proteins into vesicles easily. Think of the golgi as the post-office of the cell- it packages and processes imports and exports.
Plant cell organelles:
Vacuole: The vacuole helps control the osmotic pressure acting on the cell. It does this by storing sugars, amino acids and even enzymes in an aqueous state. It is maintained at a slightly acidic pH (below 7).
Cell wall: A protective external layer of cellulose which helps maintain the plant cell shape. When a plant cell is full with water, the internal water pushes the cell membrane against the cell wall, making it adopt a turgid shape. When a plant cell is low on water, there is less turgor pressure acting on the cell wall so the cell becomes flaccid. A good example to demonstrate this is the guard cells of the stomata.
Chloroplast: The chloroplast is the site at which photosynthesis occurs in plant cells. Chloroplasts are filled with a green pigment called chlorophyll, which helps couple light energy provided by the sun to sugar synthesis (glucose/sucrose).
Endoplasmic Reticulum: The endoplasmic reticulum, or ER, plays an important role in protein synthesis and lipid synthesis. It surrounds the nucleus and is divided into the RER (rough ER) and SER (smooth ER).
RER: The RER is described as 'rough' because when viewed under a microscope, one will see it is covered in ribosomes. The RER, therefore, is the site of protein synthesis, more specifically translation, as this occurs at the ribosome.
SER: The SER lacks these ribosomes and instead carries out the role of lipid production, as well as hormone production
ENDOCYTOSIS
EXOCYTOSIS
Intracellular transport:
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