what is the function of the cell surface membrane?
it regulates the movement into and out of the cell. it has receptor molecules on it to which allow it to respond to chemicals such as hormones
Describe the structure of the nucleus
it is a large organelle surrounded by a nuclear envelope (a double membrane), which contains many pores that enable molecules to enter and leave. the nucleus contains chromatin (material in which chromatin is made), it contains a nucleolus which is responsible for the ribosome production
what are chromosomes made of?
Chromosomes are made of sections of linear DNA tightly wound around proteins called histones
what is the function of a nucleus?
the nucleus controls the cells activity by controlling the transcription of DNA. DNA contains instructions to make protein, the pores allow substances to move between the nucleus and the cytoplasm. The nucleus makes ribosomes
Describe the structure of mitochondria
usually oval shaped, they have a double membrane, the inner one is folded to form structures called cristae, inside the inner membrane is the matrix formed by the cristae, the matrix contains enzymes required for aerobic respiration, producing ATP
what is the function of mitochondria?
mitochondria is a site of aerobic respiration, aerobic respiration produces ATP which is a common energy source in the cell
Describe the structure of chloroplast
small flattened structure found in plant cells, surrounded by a double membrane, contains thylakoid membrane (membrane inside the cell) the thylakoid membranes are stacked up to form grana. grana are linked together by lamellae (thin flat pieces of thylakoid membrane)
what is the function of chloroplasts?
it is the site of photosynthesis, the light dependent stage takes place in the thylakoids as that is where the chlorophyll is present, the light independent stage takes place in the stroma (thick fluid in the chloroplast)
what is the structure of the Golgi apparatus?
a group of fluid filled membrane bound sacs (vesicles are often seen at the edge of the sacs)
what is the function of the Golgi apparatus?
it modifies and packages proteins and lipids into Golgi vesicles, the vesicles then transport the proteins and lipids to the required destination. the Golgi apparatus also forms lysosomes
what are Golgi vesicles?
a small fluid filled sac in the cytoplasm surrounded by a membrane, produced by the Golgi apparatus, it stores lipids and proteins made by the Golgi apparatus and transports them out of the cell (via the cell surface membrane)
what is a lysosomes function?
a round organelle surrounded by a membrane, they contain hydrolytic enzymes called lysozymes enzymes that break down biological molecules, damaged organelles and pathogens
describe the structure of a ribosome?
formed from a large sub unit and a small subunit. 70s are found in prokaryotes, mitochondria, chloroplasts (make of 50s and 30s). 80s found in eukaryotes
what is the function of ribosomes?
it is the site of protein synthesis
describe the structure of the rough endoplasmic reticulum (RER)
a system of membranes enclosing a fluid filled space continuous with the nucleus envelope, surface is covered in ribosomes
what is the function of the RER?
it folds and processes proteins that were produced by the ribosomes
what is the structure and function of the smooth endoplasmic reticulum?
its a system of membranes enclosing a fluid filled space, it processes, stores and transports lipids and carbohydrates
what is the cell wall made of and what does it do?
it is made of chitin and it provides structural support to the cell, prevents shape change
what is the structure and function of the vacuole?
its a membrane bound organelle that contains cell sap, it helps to maintain the pressure inside the cell and keep its shape, this helps the plant from wilting
Describe the role of lysosomes in digesting bacteria
The vesicle (containing bacteria) known as the phagosome, fuses with a lysosome which then release hydrolytic enzymes to break down the bacteria
