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
describe smooth endoplasmic reticulums:
structure
functions
Structure
• A network of membranes without
ribosomes attached.
Functions
• Synthesize fats and steroids,
eg. sex hormones
• Helps to detoxification by converting
harmful substances into harmless
materials
describe golgis apparatus:
structure
function
Structure
• Stack of flatten discs.
• Secretory vesicles pinch off from the
ends of the discs.
Functions
• Chemically modifies, stores and
repackages substances from the ER
into vesicles for export out of the cell.
Modifies, stores substances made by the ER
2. Repackages these substances in vesicles for secretion out of the cell
what happens in the golgi apparatus
- Vesicles transport substances within the cell. Small vesicles containing
substances made by the ER are pinched off from the ER. - Vesicles then fuse with the Golgi
apparatus and release their contents
into the Golgi apparatus. The substances made by the ER may be
modified inside the Golgi apparatus. - Secretory vesicles containing these modified substances are pinched off from the Golgi apparatus. They then move to fuse with the cell surface membrane.
- Secretory vesicles fuse with the cell surface membrane and their contents are released outside the cell.
describe mitochondria:
function
structure
Structure
• Rod-shaped, with highly intricate
internal folds.
Functions
• Powerhouse of the cell - aerobic
respiration occurs here: food
substances are oxidised and energy is
released for cellular functions and
activities.
which cell is likely to contain large numbers of mitochondrions
muscle cell
describe chloroplasts:
structure
function
structure
• Oval structures which contains a green pigment called chlorophyll
function
• Is essential for photosynthesis
what are vacuoles
Vacuoles store substances within the cell.
compare animal cells vacuoles to plant cells vacuole
• Animal cells have many small vacuoles containing water and food substances.
• Plant cells have a large central vacuole containing cell sap.
differences between plant cell and animal cell
animal cell
-cell wall absent
-chloroplast absent
-centrioles present
-numerous small vacuoles
plant cell
-cell wall present
-chloroplast present
-centrioles absent
-a large central vacuole
what is differentiation
• Multicellular organisms are made up of different types of cells which perform different specific functions.
• Cells reproduce by cell division. The new cells then differentiate or specialise. Differentiation is
the process by which a cell becomes specialised for a specific function.
Why are there so many different types of cells in living organisms, e.g. blood cells, nerve cells, muscle cells,
Different cells have specialised structures and functions.
The different types of cells work together to perform a specific
function.
name 4 structures that help red blood cells perform more efficiently and explain
-Contains a red pigment called haemoglobin, haemoglobin binds to oxygen and transports it to all parts of the body
- Nucleus is absent, enables the cell to store more haemoglobin and transport more oxygen
-Circular biconcave shape, to increase surface area-to-volume ratio so that oxygen diffuses into and out of the cell at a faster rate.
-Elastic, squeeze through blood capillaries easily
name 2 structures that help root cells perform more efficiently and explain
-Long and narrow protrusion, increases surface area-to-volume ratio for faster rate of osmosis of water / faster rate of diffusion of dissolved mineral salts
-Large number of mitochondria, release large amounts of energy during aerobic respiration for the active transport of
mineral salts against a concentration gradient
- no chloroplast for more space for mineral salts and water to be taken in
name 2 structures that help muscle cells perform more efficiently and explain
-Large number of mitochondria, release large amounts of energy during aerobic respiration for the contraction of the muscle cells
-elongated and cylindrical in shape, congains many nuclei and mitochondria
describe the 2 ways we see cells
Longitudinal section
(LS): cutting along the long axis of the cell
Transverse section (TS): cutting at right angles to the longitudinal plane
does red blood cell have mitochondria?
no
(graph drawing) independent variable is ? dependent variable is ?
independent, x
dependent, y
