2.1) Cell structure Flashcards
magnification?
microscopy
how much bigger the image is compared to the real size
Formula for magnification?
Resolution
microscopy
the distincition between two objects/points that are close together
Unit conversions?
microscopy
1 mm = 1,000 µm
1 µm = 1,000 nm
1 nm = 1,000 pm
Light (Optical) microscope
microscopy
- Uses visible light and glass lenses.
- resolution: 200 nm
- magnification: x1,500
- looks at whole cells (living) or tissues at a low resolution
Preparation of Specimens for Light Microscopy
microscopy
Preparation of Specimens for Light Microscopy
Staining: Improves contrast.
Methylene blue: Stains DNA/nuclei.
Iodine: Stains starch (blue-black) and cellulose.
Acetic orcein: Stains chromosomes red.
Sectioning: Thin slices of tissue are cut using a microtome.
Mounting: Specimen placed on a slide with a cover slip.
Dry and wet mounts: Used depending on whether cells are living or fixed.
Laser Scanning Confocal
microscopy
- Uses lasers to scan specimens stained with fluorescent dyes.
- Higher resolution than light
- Moderate magnification
- Produces 3D images; focuses on different depths.
Transmission Electron Microscope (TEM)
microscopy
- Electrons pass through thin specimens.
- resolution: 0.1 nm
- magnification: x1,000,000
- High resolution; 2D images of internal structures.
microscopy
Describe, Define, Draw
Plasma Membrane
Eukaryotic organelles
Description:
* made of mainly lipids and proteins
Function:
* regulates the movement of substances in and out of the cell
* Receptor molecules on it respond to chemical messengers
(hormones)
Describe, Define, Draw
Cell wall
Eukaryotic organelles
Description:
* rigid structure that surrounds a plant cell
* made of cellulose ( the carbohydrate)
Function:
* supports plants cells
* provides structure and stability
Describe, Define, Draw
Nucleus
Eukaryotic organelles
Description:
* Organelle surrounded by a nuclear envelope (double membrane)
* nuclear envelope contains pores
* Contains chromatin (made from DNA and proteins)
* Contains the nucleolus
Function:
* controls the cell’s activites (controls transcription)
* DNA contains instructions to make proteins
* Pores in the nuclear envelope allow substances to move between the nucleus and the cytoplasm
* the nucleolus makes ribosomes
Describe, Define, Draw
Lysosome
Eukaryotic organelles
Description:
* round organelle surrounded by a membrane
* no clear internal structure
Function:
* contains digestive enzymes
* digests invading cells
* breaks down worn out components of the cell
Describe, Define, Draw
Ribosome
Eukaryotic organelles
Description:
* very small organelle
* floats free in the cytoplasm and is attached to the RER
* made up of proteins and not RNA
* not membrane bound
Function:
* protein synthesis
Describe, Define, Draw
Rough Endoplasmic Reticulum
(RER)
Eukaryotic organelles
Description:
* surface is covered with ribosomes
* a system of membranes enclosing a fluid-filled space
Function:
* folds and processes proteins that have been made at the ribosomes in its lumen
* Transports proteins to the Golgi apparatus via vesicles
Describe, Define, Draw
Smooth Endoplasmic Reticulum
(SER)
Eukaryotic organelles
Description:
* a system of membranes enclosing a fluid-filled space
* No ribosomes (smooth surface).
Function:
* synthesises and processes lipids
* Makes lipids & steroids (e.g., hormones, membrane components).
* Detoxifies harmful substances (in liver cells).
* Stores calcium ions (in muscle cells).
Describe, Define, Draw
Vesicle
Eukaryotic organelles
Description:
* A small fluid-filled sac in the cytoplasm
* membrane bound
Function:
* Transports substances in and out of the cell via the plasma membrane and between organelles
Describe, Define, Draw
Golgi Apparatus
Eukaryotic organelles
Description:
* a group of fluid-filled flattened sacs
* membrane bound
* vesicles at the end of the sacs
Function:
* it processes and packages new lipids and proteins
* it makes lysosomes
Describe, Define, Draw
Mitochondrion
Eukaryotic organelles
Description:
* oval-shaped
* double membrane
* the inner membrane is folded to form cristae
* inside of cristae is the matrix (contains enzymes for respiration)
Function:
* aerobic respiration, ATP is produced
Describe, Define, Draw
Chloroplast
Eukaryotic organelles
Description:
* small flattened structure
* double membrane bound
* membranes stacked up in some parts of the chloroplast to form grana
* grana are linked by lamellae
Function:
* photosynthesis takes place
* some in grana and some in stroma (thick fluid in the chloroplast)
Describe, Define, Draw
Centriole
Eukaryotic organelles
Description:
* small, hollow cylinders
* made of microtubules (tiny protein cylinders)
* mostly in animal cells, some in plant cells
Function:
* involved with the separation of chromosomes during cell division
Describe, Define, Draw
Cilia
Eukaryotic organelles
Description:
* small, hair-like structures found on the surface membrane of some animal cells
* microtubules in the centre
Function:
* the microtubules allow the cillia to move
* this movement moves substances along the cell surface
