3.2.1.1 Structure Of Eukaryotic Cells Flashcards
What are the three points of the cell theory?
1) all living organisms are made up of one or more cells
2) cells are the basic functional unit in living organisms
3) new cells are produced from pre-existing cells
What is a eukaryotic cell?
A eukaryotic cell is a cell which contains a nucleus
List the organelles in an animal cell:
Rough endoplasmic reticulum
Smooth endoplasmic reticulum
Cell-surface membrane
Ribosomes
Mitochondria
Cytoplasm
Golgi apparatus
Golgi vesicles
Nuclear membrane
Nuclear pores
Nucleolus
Centrioles
Lysosomes
List the additional organelles in a plant cell:
Chloroplasts
Vacuole
Cell wall
Give 2 features of algal cells
They can be unicellular or multicellular
They can photosynthesise
Give 2 features of fungal cells
They can be unicellular or multicellular
They cannot photosynthesise
Describe the structure of the cell-surface membrane
Formed from a phospholipid bilayer
Phospholipid molecules attached around the outside of the cell
Describe the function of the cell-surface membrane
Surrounds all cells
Controls the exchange (entrance and exit) of materials between the internal cell and the external environment
Describe the structure of the nucleus
Relatively large and spherical
Nuclear envelope is a double membrane which separates the nucleus from the cytoplasm
Nuclear pores allow the entrance and exit of molecules (ribosomes and RNA) from the nucleus
Contains chromatin which is the material that chromosomes are made from
The nucleolus is where RNA and ribosomes are produced
Describe the function of the nucleus
Controls protein synthesis
Retains genetic information as DNA and chromosomes
Manufactures RNA and ribosomes (nucleolus)
Where DNA is replicated and transcripted
Describe the structure of the mitochondria
Surrounded by a double membrane
The inner membrane is folded to form cristae
The matrix is formed by the cristae and contains enzymes needed for aerobic respiration and ATP production
The matrix also contains DNA and ribosomes for replication
Describe the function of the mitochondria
Where aerobic respiration takes place
Where ATP is produced
Describe the structure of the chloroplasts
Surrounded by a double membrane
Thylakoids contain chlorophyll and stack to form grana
Grana are joined together by lamellae
The stroma contains enzymes needed for photosynthesis
Also contains DNA and ribosomes (for replication)
Describe the function of the chloroplasts
The site of photosynthesis
The light-dependant stage takes place in the thylakoids
The light-independant stage takes place in the stroma
Describe the structure of the ribosomes
Formed in the nucleolus
Found freely in the cytoplasm of all cells, or on the rough endoplasmic reticulum
A complex of RNA and proteins
80s ribosomes are larger and found in eukaryotes, but 70s ribosomes are smaller and found in prokaryotes
Each ribosome is made up of two subunits
Describe the function of the ribosomes
The site of translation for protein synthesis
Describe the structure of endoplasmic reticulum
Sheet-like 3D membranes
It is continuous with the nuclear envelope
It is formed into cisternae (folds)
The rough endoplasmic reticulum has ribosomes on its surface whereas the smooth endoplasmic reticulum has no ribosomes on its surface
Describe the function of the rough endoplasmic reticulum
Processes proteins made by the ribosomes in protein synthesis, and sends them to their correct locations
Describe the function of the smooth endoplasmic reticulum
Involved in the synthesis and storage of lipids and carbohydrates
Describe the structure of the Golgi apparatus
Folded sacs of membrane that form cisternae
Vesicles pinch off from the cisternae to form secretary vesicles
Describe the function of the Golgi apparatus
Modifies proteins and lipids before packaging them into Golgi vesicles
The vesicles transport the proteins and lipids to their required destination
Describe the structure of the permanent vacuole
A fluid-filled sac in plant cells
Surrounded by a single membrane called the tonoplast, which is partially permeable
Describe the function of the permanent vacuole
Supports plant cells by making them turgid
Contain sugars and amino acids so acts as a temporary food store
Contains pigments to colour plants
Describe the structure of the cell wall
Formed outside of the cell membrane
Microfibrils of cellulose embedded in a matrix
The middle lamella forms the boundary between cells
Describe the function of the cell wall
Provides structural strength to the cell
Prevents it bursting under osmotic pressure
Describe the structure of lysosomes
Formed from vesicles which contain enzymes that break biological molecules down
Describe the function of lysosomes
Break down waste materials such as old organelles and dead cells- process called autolysis
Release enzymes to destroy materials around the cell
What is specialisation?
When cells within organisms become specialised to carry out a specific function, meaning they have specific adaptations that enable them to carry out their functions
What is differentiation?
The process by which a cell becomes specialised for a specific function
How might cells differentiate?
Change in shape of the cell
Change in size of the cell
Changes to organelles in the cell
Changes to the proteins it produces
What is a tissue?
A tissue is a group of similar cells that work together to carry out a specific function
What is an organ?
An organ is a group of similar tissues that work together to carry out a specific function
What is an organ system?
An organ system is a group of different organs that work together to carry out a specific function
