Cell Functions And Structures Flashcards
What are the distinguishing functions of eukaryotic cells
It has a cytoplasm containing membrane bound organelles and DNA enclosed in the nucleus
Describe the structure of the cell surface membrane
2 rows of phospholipids line up pointing tail to tail to make a phospholipid bilayer
Proteins are included in the bilayer
What makes up a phospholipid
Hydrophilic phosphate heads and hydrophobic fatty acid tails
What is the adaptations and functions of the cell surface membrane
It is selectively permeable which enables control of passage of substances in/out of the cell
It has molecules/receptors/antigens on the surface allowing surface recognition
Describe the structure of the nucleus
Has a nuclear envelope, nucleoplasm, nucleolus and protein/histone bound linear DNA
What is the structure of the nuclear envelope
Double membrane
Has nuclear pores
What is the nucleolus and the nucleoplasm
The dense region in the nucleus and the ‘cytoplasm’ of the nucleus
What are the types of DNA molecules in protein/histone bound linear DNA? How condensed are they
Chromatins (condensed) and chromosomes (highly condensed)
What is the function of the nucleus
Holds/stores genetic info which codes for polypeptides
Site of DNA replication
Site of transcription (part of protein-synthesis) which produces mRNA
Nucleolus makes ribosomes/RNA
Describe the structure of ribosomes
Made of ribosomal RNA and protein
Not a membrane bound organelles (free in cytosol or attached to ER)
What is the function of a ribosome
It is the site of protein-synthesis (translation)
Make proteins
How are cells adapted for protein secretion
They have lots of ribosomes
Describe the structure of rER and sER
Network of membranes
(Rough: has ribosomes and is continuous with nuclear envelope)
What is the function of rER
The ribosomes on the surface synthesise proteins
Proteins are processed/folded/transported inside the ER
Proteins are packaged into vesicles for transport
What is the function of the sER
Synthesises and processes lipids, for example cholesterol and steroid hormones
What is the main difference between the Golgi apparatus and the Golgi vesicles
The Golgi apparatus is flattened membrane sacs whilst the vesicles are small membrane sacs
Describe the structure of the Golgi apparatus and the Golgi vesicles
Flattened and small membrane sacs
What are the 2 ends of the Golgi apparatus? Where do they appear
Cis (next to ER) and trans (across from ER)
Where does product leave and enter in the Golgi apparatus
The cis end receives products
Products leave through the trans end
What is the function of the Golgi apparatus
Modifies proteins (eg adds carbs to produce glycoproteins)
Modifies lipids (eg adds carbs to make glycolipids)
Packages proteins/lipids in to the Golgi vesicle
Produces lysosomes (a type of Golgi vesicle)
What is the function of the Golgi vesicles
Transports proteins/lipids to their required destination
Eg moves and fuses with the cell surface membrane
Describe the structure of a lysosome
A type of Golgi vesicle
Hydrolytic enzymes in a membrane sac
What is the function of lysosomes
Release hydrolytic enzymes
Break down or hydrolyse pathogens or worn out cell components
What are hydrolytic enzymes called
Lysozymes
Describe the structure of the mitochondria
Consists of an outer membrane, cristae (an inner membrane fold) and a matrix
What does the cristae give the mitochondria
A large surface area
What does the matrix contain
Smaller 70s ribosomes
Circular DNA
What is the function of mitochondria
Site of aerobic respiration
Produces ATP for energy release
Describe the structure of chloroplasts
It has a double membrane, stroma, lamella, and grana
What does the stroma contain in the chloroplasts
Thylakoid membrane
Smaller 70s ribosomes
Circular DNA
Starch granules/lipid droplets
What is the lamella and grana in chloroplasts
Lamella = thylakoid linking grana
Grana = stacks of thylakoid
What is the function of chloroplasts
To absorb light energy for photosynthesis
To produce organic substances eg carbs and lipids
Describe the structure of the cell wall
Composed of the polysaccharide, cellulose in plants and algae
Composed of polysaccharide containing nitrogen, chitin in fungi
What is the function of the cell wall
Provides mechanical strength to the cell preventing the cell changing shape or bursting under pressure due to osmosis
Describe the function of the vacuole in plant cells
Cell sap surrounded by a tonoplast membrane
What is the function of the vacuole
Maintains tugor pressure stopping plants from wilting
Contains cell sap which stores sugars, amino acids, pigments and any waste chemicals
