Plant cells Flashcards
List some of the main differences of plant cells to animal.
- Plants have cell walls
- Rectangular shape rather than round
- Has chloroplast
- Uses starch as stored energy rather than glycogen
What are the functions of a cell wall?
- Structural support
- Filter
- Prevents overexpansion due to water content
What is the cell wall comprised of?
Mainly cellulose (long chains of glucose)
What are the three layers of a cell wall?
- Primary wall
- Secondary wall
- Middle lamella
What is cellulose?
The main makeup of the cell wall, it is made mainly of glucose molecules.
It can be used to make natural products such as paper and plastics, cotton is almost pure cellulose.
What is pectin?
Abundant in young tissues as part of the cell wall.
Used as a gelling agent (i.e. thickening agent in things like jelly or jams)
What are examples of fruits low in pectin?
Peaches, strawberries, blueberries and raspberries.
What are examples of fruits high in pectin?
Citrus, apples,
Describe the primary wall component of the cell wall?
- A thin, permeable flexible layer formed early in the life of the cell.
Describe the secondary wall component of the cell wall?
- internal to the primary wall
- Thick and permeable
- Formed after the cell is fully grown
What is the secondary wall comprised of?
Lignin and cellulose
What is lignin?
- Difficult to break down
- gives the woody strength
- protects against pathogens and consumption by herbivores
Describe the middle lamella component of the cell wall.
Outermost layer of the cell wall
Forms the interface between adjacentcells (glues)
What is the middle lamella comprised of?
Pectin
What are plamodesmata?
- Junctions between adjacent cells
- Pathways for transport of sugars, amino acids and signalling molecules between cells
- Uses the symplatic / cytoplasm pathway
Where does the apoplastic pathway carry nutrients?
Through the cell wall
Where does the symplastic pathway carry nutrients?
Through the cytoplasm.
What are flagella and cilia and how do they differ?
They are both hairlike structures on the surface of cells.
Flagella are longer and generally present in singular or lower numbers.
Cilia are shorter and occur in greater numbers.
What is the cytoskeleton of a cell?
Supportive strucutre for interior.
What is the cytoskeleton made from?
Made up from microfilaments and microtubules.
What are microtubules and what are they made from?
Hollow tubules composed of two different types of
molecules, alpha (α) tubulin and beta (β) tubulin.
What is mitochondria?
- Site of O2 consumption
- Folded membrane structure to increase SA: V.
What are chloroplasts?
- SIte of photosynthesis
- Trap light energy
- Double membrane strcuture
What does the stroma (inside) of chloroplasts contain?
A series of thylakoids in stacks which are called grana.
What is the golgi apparatus?
The site of synthesis and secretion of polysaccharides that make up the cell wall.
What is the Endoplasmic Reticulum? ER
Rough - involved in membrane and protein synthesis.
Smooth - Lipid synthesis
What are the steps of the cell cycle?
G1 - Interphase: Rapid cell growth
S - Interphase: DNA replicates
G2 - Interphase: Growth in prep for mitosis, organelles are doubled
Mitosis: (Prophase, metaphase, anaphase and telophase) The splitting of the cell into two.
Describe the Prophase step of mitosis.
- Chromatin condenses into chromosomes
- Spindle fibres form and attach to the centromeres.
Describe the metaphase step of mitosis.
- Spindles attach microtubules to the sister chromatids
- Pairs of chromatids begin moving towards the equator
Describe the anaphase step of mitosis.
- Sister chromatids are pulled to either end
- Cell begins to elongate
Describe the telophase step of mitosis.
- Chromosomes decondense into chromatin
- Spindles break down
- Membranes begin to form around each side
Describe the cytokinesis step of mitosis.
The two halves completely separate, forming identical daughter cells.
