cell structure

• cell membrane - a thin outer skin that controls what enters and leaves the cell - selectively permeable - made up of thin layers on lipids and proteins - holds the content of the cell in
• cytoplasm - liquid part of the cell made up mostly of water - chemical reactions occur here
• the cytoplasm minus all the organelles is known as the cytosol
• nucleus - control centre of the cell - contains dna - surrounded by a double membrane with many pores which allow chemicals to pass in and out of the nucleus
• when a cell isn't dividing the chromosomes are usually in a thin thread like form called chromatin
• ribosomes - tiny round structures that are made of protein and rna - function is to make protein
• mitochondrion - double membrane with inner folding of cristae - aerobic respiration occurs here - have their own dna
• chloroplasts - plant cells only - photosynthesis occurs here - have their own dna and replicate themselves
• cell wall - plant cells only - gives shape and support and strength to plant cells - made from cellulose and is fully permeable
• large vacuole - plant cell only - large fluid filled sac - stores water, food and waste - helps to maintain the shape of the plant cell (turgid)
• prokaryotic cells - cells that do not have a membrane enclosed nucleus - primitive - usually small - do not have a mitochondria or chloroplasts - eg. bacteria
• eukaryotic cells - cells that have a enclosed nucleus - larger than prokaryotic cells - contain mitochondria and chloroplasts - more advanced than prokaryotic cells - eg. animal kingdoms