Cell Structure Flashcards
Prokaryotic
Prokaryotic are single celled organisms
Plasma membrane (cell surface membrane) (description)
Found on the surface of animal cells and just inside of plant cells, made up of mostly lipids and proteins.
Plasma membrane (cell surface membrane) (function)
Regulates the movement of substances in and out of the cell. Has receptor molecules allowing it to respond to chemicals like hormones.
Cell wall (description)
A rigid structure that surrounds plant cell. It’s mainly of the carbohydrate cellulose.
Cell wall (function)
Supports plant cells
Nucleus (description)
A large organelle surrounded by a nucleur envelope, containing many pores. The nucleus contains chromatin and contains the nucleolus
Nucleus (function)
The nucleus controls the cells activities (controls the transcription of DNA). The DNA contains instructions of making proteins. The pores allow the movement of substances (RNA) to move between the nucleus and the cytoplasm. The nucleolus makes ribosomes.
Lysosomes (description)
A round organelle, surrounded by membrane with no clear internal structure.
Lysosome (function)
Contains digestive enzymes, which are kept separate from the cytoplasm by the surrounding membrane, these can digest invading cells and break down debris or worn out components of the cell.
Ribosomes (description)
A small organelle that floats freely or that is attached to the rough Endoplasmic reticulum made up of proteins and RNA. No membrane.
Ribosome (function)
The site of where proteins are made.
RER (description)
A system of membranes enclosing a fluid filled space. Surface covered by ribosomes.
RER (Function)
Folds and processes proteins made by ribosomes.
SER (description)
Similar to RER, but has no ribosomes (smooth)
SER (function)
Synthesis and processes lipids.
Vesicles (description)
A small fluid-filled sac in the cytoplasm carried by a membrane.
Vesicles (function)
Transports in and out of the cell (via the plasma membrane) and between some organelles. These are sometimes formed from the golgi apparatus or endoplasmic recticulum, others are formed from the cell surface.
Golgi apparatus (description)
A group of fluid-filled membrane-bound, flattened sacs, vesicles are often the edges of the sacs.
Golgi apparatus (function)
Processes and packages new lipids and proteins. Also makes lysosomes.
Mitochondria (description)
Usually an oval-shaped. They have a double membrane. The inner one is folded to fork structures called the cristae. Inside which uses enzymes in respiration.
Mitochondria (function)
The site of aerobic respiration, with the production of ATP. Found in a large number if cells and are very active and require a lot if energy.
Chloroplast (function)
A small, flattened structure found in plant cells. Surrounded by a double membrane, membranes inside are called thylakoid membranes. These are stacked up in some parts of the chloroplasts to form the grana. These are linked together by the lamellae, thin, flat pieces if thylaloud membrane.
Chloroplast (function)
The site of where photosynthesis takes place. Some take place in the grana and other parts in the stoma. (Thick fluid found in the chloroplasts.)
Transcription -
DNA contained within a double membrane and the chromosomal DNA is too large to leave, therefore they are copied into the site of protein synthesis the ribosome
The DNA that contains the gene unwinds under the control of the DNA helicase (breaking of hydrogen bonds between bases)
Only one of these stands are taken to be synthesised, the antisense strand doesn’t code for a protein acts as a template.
RNA nucleotides then pair on the antisense strand with complementary base pairing with uracil instead of thymine
Phosphodiester bonds then formed between RNA nucleotides, achieved from RNA polymerase, the completed short strand is mRNA. Has the same base sequences that make up the gene but with the presence of uracil.
Then detaches from the template and leaves through the nuclear pore. The DNA helix reforms. Then travels to the ribosome in the cell cytoplasm.
Translation -
Eukaryotic cells ribosomes contain two subunits with a small and large.
These are a form of RNA known as rRNA it maintains the structure of the stability of protein synthesis and a biochemical role in catalysing the reaction.
mRNA binds to a specific site on the small subunit of the rRNA, it is held in position while mRNA is decoded into a sequence of amino acids (translation)
Anticodons will bind to codons (complementary base pairing of Uracil)
tRNA anticodons will bind to complementary codons along the mRNA, AA brought together in a right sequence to form a primary structure of a protein
Ribosomes act as the binds sites for mRNA on the small subunit and tRNA catalyses the assembly of the proteins.
