A2.2 - cell structure and micrographs (3b) Flashcards
what are prokaryotic cells?
bacterial cells
- (Gram positive eubacteria such as Bacillus or Staphylococcus)
what are the components of all prokaryotic cells?
cell wall, plasma membrane, cytoplasm, naked DNA, 70S ribosome
what are extra 3 components prokaryotic cells may contain?
plasmid, flagellum, pili
what is the function of the cell wall?
made of peptidoglycan, and protects and maintains the shape of the cell
what is the function of the plasma membrane?
partially permeable and selective barrier
- lipid bilayer with embedded proteins to enclose cytoplasm, control movement of substances in and out of cells and supporting cell recognition and communication
what is the function of the cytoplasm?
fluid medium, made of matrix and water where metabolic reactions occur
what is the function of the naked DNA?
DNA found in a loop called a nucleoid
what is the function of DNA?
stores genetic code (sequence of nucleotides) and allows this to transfer during protein synthesis and cell division
what is a nucleoid?
a nucleoid is a region of cytoplasm containing the naked DNA
what is the function of the 70S ribosome?
the site of protein synthesis via translation
what is the function of the plasmids?
small loops of DNA that can be transferred, containing one or a few genes that are not essential in normal conditions but which may aid survival in unusual conditions
what is the function of the pili?
hair-like extensions allowing adherence to surfaces or other bacteria for plasmid DNA transfer
what is the function of the flagellum?
longer than the pili and involved in the movement of the bacterial cell using a motor protein
what are the structures found in mitochondria?
crista, matrix, inner membrane, outer membrane, DNA, 70S ribosome, intermembrane space
what is the role of the cristae?
the cristae are foldings of the inner membrane, which is the site of most ATP production
what is the role of the matrix?
the matrix is found within the inner membrane, containing enzymes for respiration
what structures are found in the nucleus?
surrounded by a double membrane containing nuclear pores
- contains chromosomes
what is the role of chloroplasts?
chloroplasts are specialised plastids and the site of photosynthesis, which converts light energy into chemical energy
what is found in the chloroplasts?
granum, inner membrane, outer membrane, stroma, 70S ribosome, starch granules, lumen, lamella, thylakoid membrane, DNA
what is the role of the granum?
granum - stacks of thylakoids to provide a larger surface area
what is the role of stroma?
stroma - contains enzymes
what is the function of the sap vacuole?
sap vacuole - a relatively large membrane sac containing water to provide rigidity and sugars to allow storage of nurtrients in plants
what is the function of the smooth and rough endoplasmic reticulum?
rough endoplasmic reticulum - a network of interconnected membranes, with ribosomes attached to produce proteins from 80S ribosomes
- tends to be found close to the nucleus, and may have connected membranes
smooth endoplasmic reticulum - a network of interconnected membranes without ribosomes attached that produce lipids and hormones
what is the function of the golgi apparatus?
golgi apparatus - stacks of sacs called cisternae, with vesicles budding off
what is the function of the secretory vesicles?
secretory vesicles - carry proteins to the plasma membrane and secrete them by exocytosis
what is the function of the outer membrane?
to compartmentalise the mitochondrial processes from those in the cytoplasm
