3.2.1.1 Structure of eukaryotic cells Flashcards
Eukaryotic cells
Examples
Animal
Plant
Algae
Fungi
Eukaryotic cells
Definition
A cell containing a membrane bound nucleus, and other membrane bound organelles
Eukaryotic cells
Structure (contents)
- cell-surface membrane
- nucleus (containing chromosomes, consisting of protein-bound, linear DNA, and one or more nucleoli)
- mitochondria
- chloroplasts (in plants and algae)
- Golgi apparatus and Golgi vesicles
- lysosomes (a type of Golgi vesicle that releases lysozymes)
- ribosomes
- rough endoplasmic reticulum and smooth endoplasmic reticulum
- cell wall (in plants, algae and fungi)
- cell vacuole (in plants)
Animal cell
Structure (contents)
- cell-surface membrane
- cell-surface membrane
- mitochondria
- Golgi apparatus and Golgi vesicles
- lysosomes (a type of Golgi vesicle that releases lysozymes)
- ribosomes
- rough endoplasmic reticulum and smooth endoplasmic reticulum
Plant cell
Structure (contents)
- cell-surface membrane
- cell-surface membrane
- mitochondria
- chloroplasts
- Golgi apparatus and Golgi vesicles
- lysosomes (a type of Golgi vesicle that releases lysozymes)
- ribosomes
- rough endoplasmic reticulum and smooth endoplasmic reticulum
- cell wall
- cell vacuole
Fungi cell
Structure (contents)
- cell-surface membrane
- nucleus (containing chromosomes, consisting of protein-bound, linear DNA, and one or more nucleoli)
- mitochondria
- Golgi apparatus and Golgi vesicles
- lysosomes (a type of Golgi vesicle that releases lysozymes)
- ribosomes
- rough endoplasmic reticulum and smooth endoplasmic reticulum
- cell wall (made of chitin not cellulose )
Algae cell
Structure (contents)
- cell-surface membrane
- cell-surface membrane
- mitochondria
- chloroplasts
- Golgi apparatus and Golgi vesicles
- lysosomes (a type of Golgi vesicle that releases lysozymes)
- ribosomes
- rough endoplasmic reticulum and smooth endoplasmic reticulum
- cell wall
Cell-surface membrane
Structure
- phospholipid bilayer
- fluid mosaic model
- mainly made of lipids and protein
Cell-surface membrane
Function
- controls the movement of substances in and out of the cell (as is selectively permeable)
- receptor molecules respond to chemicals such as hormones
Nucleus
Structure
- Nuclear envelope
- Nuclear pores
- Nucleoplasm
- Chromosomes
- Nucleolus
Nucleus
Function (overall)
- controls cell activities e.g transcription of DNA
- contains instructions for protein synthesis
- makes ribosomes
- contain cells genetic information that can be transmitted to next generation
Function of the nuclear envelope in the nucleus
- controls entry and exit molecules
- controls reactions within
Function of nuclear pores in the nucleus
- allows passage of large molecules
- e.g. RNA to move from nucleus to cytoplasm
Function of the nucleoplasm in the nucleus
- makes up bulk of nucleus
- structural support
Function of chromosomes in the nucleus
-holds protein bound, linear DNA
Function of the nucleolus in the nucleus
-produces ribosomal RNA and ribosomes
Mitochondria
Structure
Double membrane
Cristae
Matrix
Function of the double membrane in the mitochondria
-control entry and exit molecules
Function of the double membrane in the mitochondria
-control entry and exit molecules
Function of the cristae in the mitochondria
- Site of oxidative phosphorylation
- Larger surface area for enzymes and other respiration related proteins
Function of the matrix in the mitochondria
- Site of link reaction and krebs cycle
- Contains enzymes and proteins involved in link reaction and Krebs cycle
- contains mitochondrial DNA and ribosomes to make them
Mitochondria
Function (overall )
- aerobic respiration
- to produce ATP/provide energy
Mitochondria
Abundancy
More abundant in more metabolically active cells
EQ: Give one piece of evidence that supports the theory that mitochondria evolved from prokaryotic cells.
- circular DNA
- smaller (70S) ribosomes
- no introns
- no proteins (histones) associated with DNA
Chloroplasts
Structure
Chloroplast envelope (double membrane) Thylakoids Grana (stacks of thylakoids, connected by lamellae) Lamellae Stroma (dense fluid inside chloroplast) DNA/ribosomes
Function of the envelope in chloroplasts
- surrounds chloroplast
- selects what enters and leaves
Function of the thylakoids in chloroplasts
- site of light-dependent stage of photosynthesis
- contains chlorophyll
- large SA for attachment of enzymes involved in the light-dependent stage of photosynthesis
Function of the grana in chloroplasts
-absorbs light for the first stage of photosynthesis
Function of the lamellae in chloroplasts
-join grana
Function of the stroma in chloroplasts
- site of light-independent stage of photosynthesis (Calvin cycle)
- contains starch grains that store excess sugars
- contains enzymes for photosynthesis
- contains DNA and ribosomes to make them
Function of the DNA/ribosomes in chloroplasts
-quick and easy manufacturing of proteins needed for photosynthesis
Chloroplasts
Function (overall)
- absorbs and uses light
- for photosynthesis
- to produce carbohydrates/sugars/lipids/protein
Golgi apparatus
Structure
- double membrane
- contains cisternae (membrane bound flattened sacs)
Golgi apparatus
Function (overall)
- -processes and packages lipids and proteins
- packages proteins (into golgi vesicles)
- transports proteins (to cell surface/vacuole)
- modifies proteins ( adds carbohydrate group to proteins- synthesis of glycoproteins)
- transports lipids
- creates lysosomes and golgi vesicles
Function of cisternae in the golgi apparatus
-large surface area for synthesis of glycoproteins
Golgi vesicles
Structure
- small fluid filled, membrane bound sac
- produced by golgi apparatus
- contains modified proteins and lipids
Golgi vesicles
Function
-stores and transports proteins and lipids made by the golgi apparatus out of the cell, via the cell surface membrane
Lysosomes
Structure
- small, round membrane bound organelle
- type of golgi vesicle
- contain digestive enzymes
- formed by golgi apparatus
Lysosomes
Function
- hydrolyse material ingested by phagocytes
- digest worn out organelles
- break down dead cells
Ribosomes
Structure
- made up of proteins and rRNA
- large and small subunit
Ribosomes
Types and location
-80S ribosomes: larger
└found in eukaryotic cells
-70S ribosomes: smaller
└found in prokaryotic cells and eukaryotic cells (in mitochondria and chloroplasts)
Ribosomes
Location in cell
- floats free in cytoplasm
- attached to rough endoplasmic reticulum
Ribosomes
Function
-site of protein synthesis
Function of cisternae in the rough endoplasmic reticulum
-large surface area for the synthesis of proteins and glycoproteins
Function of ribosomes in the rough endoplasmic reticulum
-site of protein synthesis
Rough endoplasmic reticulum
Function (overall)
- protein and glycoprotein synthesis
- secretes vesicles containing proteins and sends them to the golgi apparatus
Smooth endoplasmic reticulum
Structure
- made up of cisternae (fluid filled, membrane bound flattened sacs)
- double membrane
Function of cisternae in the smooth endoplasmic reticulum
-large surface area for the synthesis of lipids and carbohydrates
Smooth endoplasmic reticulum
Function
-synthesises, stores and processes lipids (and carbohydrates)
-makes and transports, lipids, steroids and hormones
Ribosomes
- site of protein synthesis
-secretes vesicles containing lipids and carbohydrates and sends them to Golgi apparatus (processes them)
Cell wall
Structure
-made of cellulose (plants) or chitin (fungi)
Cell wall
Function
- rigid
- gives cell strength, shape and support
- prevents bursting (when water enters cell by osmosis)
Cell vacuole
Structure
-fluid filled sac
└ contains sugars, salts, amino acids, waste and pigment.
-tonoplast (single membrane)
Cell vacuole
Function
- contain cell sap (weak solution of sugars and salts)
- temporary food store
- pigment attracts pollinating insects
- isolates any unwanted chemicals
- maintains pressure inside cell
Cytoplasm
Function
-site of chemical reactions
EQ: Structures found in prokaryotic cells but not in eukaryotic cells
- Capsule / glycocalyx / slime layer
- Circular / ring of / non-linear DNA / DNA without histones
- Plasmid
- Flagellum
- Pilus
- Small / less dense / 70s ribosomes
EQ: organelle that you would expect to find in large numbers in a mucus-secreting cell and describe its role in the production of mucus.
-Golgi (apparatus)
-Package/process proteins
OR
-Rough endoplasmic reticulum/ribosomes
-Make polypeptide/protein/forming peptide bonds
OR
-Mitochondria
-Release of energy/make ATP
OR
-Vesicles
-Secretion/transport of protein
Why do organelles in multicellular eukaryotic cells vary?
Cells become specialised to carry out specific function. A cell’s shape and organelles helps it to carry out that specific function.
What is the organisation of cells?
- specialised cells are organised into tissues
- tissues into organs
- and organs into organ systems
Tissue
Definition
- a group of cells
- or one or more types
- specialised to perform a particular function
Organ
Definition
- a group of tissues
- working together to perform a particular function
Organ system
Definition
- a group of organs
- working together to perform a particular function
EQ: Example of a plant tissue
xylem / phloem / epidermis / mesophyll / palisade / spongy mesophyll
