Cells Flashcards
What are the characteristics of the nucleus?
Largest cell organelle
Contains DNA in chromosomes
DNA codes for protein synthesis
What is the nuclear membrane or envelope?
Double membrane with pores that allows exchange of substances in and out of the nucleus
What is present within the nuclear envelope?
Nucleoplasm
What is the nucleolus?
Contains DNA which codes for rRNA and produces ribosomes
What is the rough endoplasmic reticulum?
Consists of a series of flattened membrane bound sacs - cisternae
Studded with ribosomes
What is the function of the rough endoplasmic reticulum?
Transports protein that are produced on attached ribosomes
What will happen to some proteins within the RER?
Some secreted
Some placed on the surface of the cell membrane
Explain the structure of smooth ER?
Same as RER without ribosomes
What is the function of SER?
Involved in lipid synthesis and detoxification of drugs
What are the characteristics of ribosomes?
Tiny organelles found in the cytoplasm
Each consists of 2 sub-units
Made of protein and rRNA
What are ribosomes main function?
Protein synthesis in a cell - proteins are made
What is the structure of the golgi apparatus?
Cisternae - series of flattened sacs - associated vesicles
May add glycoproteins or lipoproteins to them
What kind of structure will be made when joining polypeptides?
Quaternary
What is the golgi apparatus’ main function?
Label, package and sort proteins for export from the cells
What are lysosomes?
Spherical sacs containing powerful digestive enzymes
Thick membrane to prevent enzymes from being released
What are lysosomes main function?
Important in phagocytosis
Fuse with other vesicles that contain something to be destroyed
Explain the structure of mitochondria:
Double membrane bound
Inner membrane folds inwards to create cristae
Explain the functions of the mitochondria:
Site of aerobic respiration
Abundant in cells with high energy requirements
Explain the structure of microtubules:
Hollow cylinders - tubulin
Form the cytoskeleton
Explain the functions of the microtubules:
Aid movement of structures within cells
Forms spindle - moves chromosomes during mitosis and meiosis
Component of cilia and flagella
Explain the structure of the cytoplasm:
Part of cell between cell surface membrane and nucleus
What is the protoplasm?
All the cell contents within cell surface membrane
What is the cytosol?
Cytoplasm excluding organelles and nucleus
What is a eukaryotic cell?
Contains membrane bound organelles and a nucleus
What is the structure of a cell wall in a eukaryotic cell?
Immediately outside the cell membrane
Composed of cellulose microfibrils
What is the cell walls main function?
Strength
Fully permeable
What is the primary cell wall made up of?
Many microfibrils
Loosely arranged for expansion as the cell grows
What is the secondary cell wall?
In a full sized cell
Additional cellulose is deposited in a lattice arrangement to provide strength
What is the middle lamella?
Links adjacent cells, composed of pectin
What is the plasmodesmata?
Narrow threads of cytoplasm pass through adjacent cell walls to allow communication
Explain the structure of the chloroplast:
Double membrane bound
Contains stroma
Thylakoid membranes stacked into grana
What is the main function of the chloroplast?
Site of photosynthesis:
