C1: Cell structure and organisation Flashcards
How do you calculate magnification
x(size of drawing in mm)/(actual size of specimen in mm)
measurements of one calibrated eyepiece graticule when the objective lens is
1) x10
2) x40
1) 10um
2) 2.5um
steps to bio drawing
SLLAPT
S - size (3/4)
L - lines ( continuous and clear)
L - labelling ( line must touch the object in str. horizontal lines)
A - accuracy (draw all relevant features, don’t add what u don’t see)
P - proportion
T - title ( drawing of a..)
take note: no shading, no stippling, drawing 3/4 of paper, animal cells -> no shape( circular kinda), plant cells-> rectangular shape
key ideas of cell theory
1)All living organisms are made up of one or more CELLS
2)The cell is the basic unit of structure and organization in organisms
3)All cells come from PRE-EXISTING CELLS
what are cells
cells are made up of organelles, they are a unit of life and consists of mass living matter called protoplasm
how do we see organelles
1) electron microscopes
black and white images
higher resolution
more than 200 000×
2) light microscopes
coloured micrographs
lower resolution
1000×
what is the function of cell surface membrane/plasma membrane and it’s structure
Structure
- Made up of lipids and proteins.
It is partially permeable.
Function
- It controls the movement of
substances into and out of the cell.
lipid: biological molecules that are not soluble in water. eg, fats, oil
describe cytoplasm
- structure
- function
Structure
• Found in sol or gel states.
• Often seems to be moving about
or streaming.
Function
• Most cellular functions and
reactions take place.
• Contains two specific constituents
called enzymes and organelles.
describe nucleus’
- structure
- function
Structure
* Consists of nucleoplasm
* Separated from the
cytoplasm by the nuclear
envelope.
* Contains chromatin and
one or more nucleoli.
Function
* Controls cell activities
* Essential role in cell
division.
describe cell walls
- structure
- function
- Present in plant cells but is absent in
animal cells
Structure - Composed of cellulose
- Fully permeable to small molecules
Functions - Protects the plant cell from injury.
- Gives the plant cell a fixed shape.
- does not control the movement in and out of the cell
name the organelles in the nucleus and their functions
an organelle is a cellular structure that performs a specific job within a cell
- nuclear envelope
outer membrane of the nucleus, separates the contents of the nucleus from the rest of the cytoplasm - nucleoplasm
the cytoplasm of nucleus - nucleoli
the dark staining region in the nucleus - chromatin
Long thread-like structures in the nucleus, made of proteins and deoxyribonucleic acid (DNA). - DNA stores hereditary information and instructions for cellular activities and cell division.
- Chromatin threads are crucial to cell division. During the process, they condense into highly coiled structures called chromosomes.
what is protoplasm?
protoplasm is a complex jelly like substance. many chemical activities that allow the cell to survive and grow are carried out in the protoplasm.
describe rough endoplasmic reticulums:
structure
function
Structure
- A network of membranes with small round structures (ribosomes) attached.
- attached to the nucleus
Functions
- Ribosomes synthesize proteins.
- The RER transports proteins to the Golgi apparatus for secretion out of the cell.
what does RER look like
• Has surface that appears rough
• Ribosomes attached to its outer surface
• Outer surface attached to the nuclear membrane
describe ribosomes:
structure
functions
Structure
• Either attached to membrane of RER or
• Lie freely in cytoplasm
Functions
• Ribosomes on RER make proteins that are usually transported out of the cell
• Ribosomes lying freely in cytoplasm make proteins that are used within the cytoplasm of the cell
