Structure of eukaryotic cells Flashcards
Describe the Structure and function of the cell-surface membrane
Structure:
-phospholipid bilayer with embedded proteins
-Selectively permeable so enables control of passage of substances in and out of cells
Function:
-Barrier between internal and external environment
Describe the Structure and function of the nucleus
-Nuclear envelope, nuclear pores, nucleolus , DNA
-controls the cells activity through transcription on mRNA
-Nuclear pores allows substances e.g. mRNA to move between the nucleus and cytoplasm
-Nucleolus makes ribosomes which are made up of proteins and ribosomal RNA
Describe the Structure and function of the mitochondria
Structure:
Double membrane – inner membrane folded to form cristae.
Matrix containing small 70S ribosomes, small circular DNA and enzymes
involved in aerobic respiration (glycolysis).
Function
- Site of aerobic respiration producing ATP for energy release
Describe the Structure and function of the Golgi apparatus
Structure
3 or more fluid filled membrane bound sacs with vesicles at edge
Function:
Receives protein from rough endoplasmic reticulum
Modifies/processes protein
Packages into vesicles e.g. for transport to cell surface membrane for exocytosis
Also makes lysosomes
Describe the structure and function of lysosomes
Structure:
Type of Golgi Vesicle containing lysozymes (hydrolytic enzymes)
Function:
Release of lysozymes to hydrolyse pathogens
Describe the Structure and function of ribosomes
Structure
Float free in cytoplasm or bound to rER. Made from 1 large and 1 small subunit.
Function
- Site of protein synthesis, specifically, translation.
Describe the Structure and function of the rough endoplasmic reticulum
Ribosomes bound by a system of membranes
Folds polypeptides to secondary / tertiary structure
Packages to vesicles, transport to the Golgi apparatus etc.
Describe the Structure and function of the smooth endoplasmic
reticulum
System of membranes
function:
synthesises and processes lipids
Describe the Structure and function of chloroplasts (plants and algae)
Structure:
Thylakoid membranes are stacked up in some parts to form grana, which are linked by lamellae. These sit in the stroma and are surrounded by a double membrane. Also contains starch granules and circular DNA.
Function:
(Chlorophyll) absorbs light for photosynthesis to produce organic substances
Describe the Structure and function of the cell vacuole (plants)
Structure
Contains cell sap – a weak solution of sugars and salts. Surrounding membrane is
called the tonoplast.
Function
Maintains pressure in the cell (stop wilting)
Stores/isolates unwanted chemicals in the cell
Describe how specialised cells are organised in complex multicellular organisms
Specialised cell – the most basic functional subunit in all living organisms, specialised for a particular function
Tissue – Group of organised specialised cells; joined and working together to perform a particular function; often with the same origin
Organ – Group of organised different tissues; joined and working together to perform a particular function
Organ system – Group of organised organs; working together to perform a particular function
Explain how epithelial cells in the small intestine are specialised for efficient absorption.
Villi and microvilli increase surface area.
Lots of mitochondria to provide energy e.g. for active transport