Cells Flashcards
Structure of mitochondrion
Has an outer membrane and an inner membrane
The inner membrane is folded to form cristae
Inside the inner membrane is a matrix containing enzymes, ribosomes and a circular DNA molecule
Function of mitochondrion
The site of aerobic respiration and responsible for producing most of the ATP in a cell
Rough endoplasmic reticulum structure
Flattened discs of membranes
Surface is covered in ribosomes
Rough endoplasmic reticulum function
Processes proteins made by the ribosomes
Nucleus structure
A large organelle enclosed by a double membrane which is perforated by pores
Contains chromosomes and one or more nucleoli
Function of the nucleus
Nuclear pores are needed to allow mRNA and ribosomes to leave and enzymes to enter
Chromosomes contain DNA which controls synthesis of proteins
Golgi apparatus structure
Stack of membrane bound, flattened sacs in the cytoplasm
Golgi apparatus function
Receives and prepares proteins synthesised on the ER for secretion from the cell.
This often involves adding carbohydrate to the proteins to make them into glycoproteins
Chloroplast structure
Surrounded by two membranes and contains a matrix called stroma which has a system of membranes running through it.
Stroma contains ribosomes, starch grains and circular DNA
Grana is stacks of thylakoids. Thylakoids hold the pigment chlorophyll.
Chloroplast function
The organelle in which photosynthesis takes place. Chlorophyll pigments capture light energy and transfer it into chemical bonds
Lysosome structure
Vesicles which contain hydrolytic enzymes
Lysosome function
Responsible for destroying worn out organelles and digesting the contents of phagocytosis
Vacuole structure
A sac bundled by a single membrane
Contains cell sap which is a solution of salts and other substances
Vacuole function
Stores waste products and other substances
Changes in volume affect the turgidity of the cell
Cell membrane structure
A phospholipid bilayer with extrinsic and intrinsic protein molecules
Function of cell membrane
A partially permeable membrane which controls which substances enter or leave the cell
Cell wall structure
Consists of cellulose microfibrils and other polysaccharides
Cell wall function
Provides mechanical support and protection
Prevents the cell from bursting
Smooth endoplasmic reticulum structure
Formed from continuous folds of membranes continuous with the nuclear envelope
SER function
Where steroids and lipids are synthesised
Ribosome structure
Very small organelle not bounded by a membrane
Consists of a large and small subunit
Made of protein and RNA
Ribosome function
Uses the information in nucleic acid to synthesise proteins
Nucleoulus function
Where ribosomes are produced
What are the the 3 stages of mitosis
Interphase, nuclear division, cytokinesis
What happens during interphase
No division takes place
What happens during nuclear division
Nucleus divides into 2
What happens during cytokenesis
Division of the cytoplasm
What is the order of the stages of the cell cycle
Prophase, metaphase, anaphase, telophase, cytokenesis
Prophase description
Chromosomes become visible because they condense
Centrioles move to opposite poles
Spindle fibres form from pole to pole
Describe metaphase
Chromosomes are pulled to the equator of the cell via spindle fibres form
Chromosomes are attached to spindle fibres via centromere
Describe anaphase
Centromeres divide into two
Spindle fibres pull sister chromatids apart to opposite poles
Energy supplied by mitochondria
Telophase description
Chromosomes have reaches their poles and become longer and thinner, and are unable to be seen by microscopes
Spindle fibres break down
Nuclear envelope and nucleolus reform
Description of cytokenesis
Formation of a cleavage by pinching it and splitting it in two
Describe the structure of a prokaryotic cell
No membrane organelles, smaller ribosomes, circular dna, cell wall that contains murein
What structures do SOME prokaryotic cells have
One or more plasmid, flagella, capsule that surrounds the cell
Describe the structure of viruses
Not classified as acellular but rather as having particles, capsid, attachment proteins
What is a hypotonic solution?
Higher water potential outside the cell, lower water potential inside the cell. Water moves inside of the cell.
