2.1.1. Structure of Eukaryotic cells Flashcards
What is the structure of the nucleus in eukaryotic cells?
Nuclear envelope (double membrane), nuclear pores, nucleoplasm (jelly-like material), chromosomes = protein-bound linear DNA, nucleolus
What is the nucleolus?
Smaller sphere where rRNA and ribosomes are produced
What is the function of the nucleus in eukaryotic cells?
Site of DNA replication and transcription; contains the genetic information for each cell
What is the structure of the smooth endoplasmic reticulum in eukaryotic cells?
Folded membranes (cisternae)
What is the structure of the rough endoplasmic reticulum in eukaryotic cells?
Folded membranes (cisternae), ribosomes on surface
What is the function of the smooth endoplasmic reticulum in eukaryotic cells?
Synthesis of lipids; stores lipids and carbohydrates
What is the function of the rough endoplasmic reticulum in eukaryotic cells?
Protein synthesis (ribosomes)
What is the structure of the golgi apparatus in eukaryotic cells?
Folded membranes (cisternae); secretary (golgi) vesicles pinch off from the cisternae
What is the function of the golgi apparatus in eukaryotic cells?
Transport, modify and store lipids; form lysosomes
What is the structure of lysosomes in eukaryotic cells?
Vesicles of digestive enzymes (e.g. phagocytosis)
What is the function of lysosomes in eukaryotic cells?
Hydrolyse phagocytic cells; completely break down dead cells; exocytosis -> release enzymes to outside of the cell to destroy material; digest worn-out organelles for reuse of materials
What is the structure of mitochondria in eukaryotic cells?
Double membrane; inner membrane (cristae); fluid centre (mitochondrial matrix); loop of mitochondrial DNA
What is the function of mitochondria in eukaryotic cells?
Site of aerobic respiration; site of ATP production; DNA codes for enzymes needed in respiration
What is the structure of ribosomes in eukaryotic cells?
Small, made up of two subunits: protein and mRNA; 80s = large ribosome in eukaryotic cells
What is the function of ribosomes in eukaryotic cells?
The site of protein synthesis
What is the structure of the vacuole in eukaryotic cells?
Filled with fluid; surrounded by a single membrane (tonoplast)
What is the function of the vacuole in eukaryotic cells?
Makes cells turgid, providing support; temporary store of sugars + amino acids; pigments may colour petals, thus attracting pollinators
What is the structure of chloroplasts in eukaryotic cells?
Surrounded by a double membrane; contains thylakoids (folded membranes embedded with pigment); fluid filled stroma (contains enzymes for photosynthesis)
What is the function of chloroplasts in eukaryotic cells?
Site of photosynthesis
What is the structure of the cell wall in eukaryotic cells?
Plants: made of microfibrils of the polymer, cellulose; Fungi: made of chitin
What is the function of the cell wall in eukaryotic cells?
Provide structural strength to the cell
What is the structure of the plasma membrane in eukaryotic cells?
Found in all cells; phospholipid bilayer - molecules embedded in and attached on the outside (e.g. proteins, carbs)
What is the function of the plasma membrane in eukaryotic cells?
Controls the entrance and exit of molecules
Describe the difference in structure between the RER and SER.
In RER, ribosomes are present.
In SER, ribosomes are not present and SER is more tubular in appearance
What are the cell walls of fungi made up of?
chitin
What are the two types of ribosomes and where are they found?
80S ribosomes - found in eukaryotes
70S ribosomes (smaller) - found in prokaryotes (as well as eukaryotic chloroplasts and mitochondria)
What is the difference in function between the RER and SER.
RER synthesises proteins and glycoproteins (as it contains ribosomes).
SER only synthesises, transports and stores lipids and carbohydrates (no ribosomes for protein synthesis
Where are ribosomes found?
cytoplasm
RER
The diagram shows a mitochondrion.
Name parts labelled X and Y.
X - Cristae
Y - Matrix
The electron micrograph shows part of a chloroplast.
Name the main substance present in the part labelled C. (1)
Starch
Describe and explain the effect on the organelle of placing it in the hypotonic solution. (4)
(outer) membrane breaks down / inner membranes / grana separate;
solution has a higher / less negative water potential; (accept description of relative concentrations)
water moves into organelle / chloroplast by osmosis / from higher to lower water potential / into more concentrated solution; (reject into cell)
organelle swells / increase in pressure and bursts;
Define organ and give an example, including the tissues it is made of.
Group of organised different tissues; joined and working together to perform a particular function
Define organ system and give an example.
Group of organised organs; working together to perform a particular function
nervous system
Define tissue and give 2 examples.
Group of organised specialised cells; joined and working together to perform a particular function; often with the same origin
epithelial tissue - lines surfaces of animal organs
xylem tissue - gives mechanical support and transports water
Define the term Eukaryotic cell
DNA is contained in a nucleus, contains membrane- bound specialised organelles
