1.3. Plant And Animal Cells As Seen With A Light Microscope Flashcards
A generalized cell shows
all the structures that may commonly found in a cell
Why do plant cells need to be stained before they are seen through a light microscope?
Because most of the cell contents are colorless and transparentt
Define cell surface membrane
A very thin membrane surrounding all cells
Cell surface membrane is also known as
Plasma membrane
All eukaryotic cells contain
Nucleus
Why is the nucleus very easy to see when looking down the microscope
It is relatively large and stains intensely
The deeply staining material in the nucleus is
Chromatin
Chromatin is a mass of
Coiled threads
The threads are seen to collect together
To form chromosomes during nuclear division
Chromatin contains ____ the molecule which contains the ________ that controls the activities of the cell.
DNA….. instructions(genes)
An even more deeply staining area inside the nucleus is
The nucleolus
Nucleolus is made up of
Loops of DNA from several chromosomes
The common number of nucleoli in each cell in a mammal is
One to five
One of the main function of nucleoli is
To make ribosomes
All the living material inside the cell is called
Protoplasm
all the living material outside the nucleus but within the cell is called
Cytoplasm
Cytoplasm is an aqueous (watery) material, varying from a ______ to a _______ consistency.
Fluid ….. jelly like
Why are organelles separated by membranes in an eukaryotic cell
so that their activities can be separated from the surrounding cytoplasm. Organising cell activities in separate compartments is essential for a structure as complex as an animal or plant cell to work efficiently.
The most numerous organelles seen with the light microscope is
Mitochondria
Mitochondria are only _______ using a light microscope
Just visible
Videos of living cells have shown mitochondria can
Move about, change shape and divide.
Mitochondria are specialized to carry out
Aerobic respiration
What resulted in discovery of Golgi apparatus
The use of special stains containing silver
What does the Golgi apparatus do
Golgi apparatus collects and processes molecules within the cell, particularly proteins.
One of the structures commonly found in animal cells but absent from plant cells is
the centriole
Plant cells differ from animal cells by posessing
Cell walls, large permanent vacuoles, and chloroplasts
How do centrioles appear to be under the light microscope
As a small structure close to the nucleus
Why is it that with a light microscope individual plant cells are more easily seen than animal cells
Because they’re usually larger, and unlike animal cells are surrounded by a cell wall
The cell wall is extra cellular. Explain what this means.
The cell wall is an extra structure, which is outside the cell surface membrane
What is the cell wall relatively rigid?
Because it contains fibers of cellulose a polysaccharide which strengthens it
What are some benefits of the cell wall?
It gives the cell a definite shape.
Prevents the cell from bursting when water enters it by osmosis, allowing large, pressures to develop inside the cell
Cell walls may be reinforced for extra strength with
Extra cellulose or a hard material called lingin
Cell walls are freely permeable
This means they allow free movement of molecules and ions through to the cell surface membrane
Plant cells are linked to neighboring cells by
pores containing fine strands of cytoplasm. These structures are called plasmodesmata(singular: plasmodesma)
Plasmodesmata are lined with
the cell surface membrane
Movement through the pores is thought to be controlled by
The structure of the pores
Vacuoles are
Sac like structures which are surrounded by a single membrane
Animal cells possess small temporary vacuoles such as
Phagocytic vacuoles
A mature plant cell possesses a _____, _______, _________ vacuole
Large, permanent, central
The plant vacuole is surrounded by a membrane called
The tonoplast
What is the function of a tonoplast
It controls the exchange between the vacuole and the cytoplasm
The fluid in the vacuole is a solution of
Pigments, enzymes, sugars and other organic compounds (including some waste products), mineral salts, oxygen and carbon dioxide
Functions of vacuoles in a plant cell
Help to regulate the osmotic properties of the cells (the flow of water inwards and outwards)
Contain the pigments which color the petals of certain flowers or parts of certain vegetables such as the red pigments of beetroots
Chloroplasts are organelles specialized for
Photosynthesis
Chloroplasts are found in
Green parts of the plants, mainly the leaves
Chloroplasts are relatively large organelles so can easily be seen with a light microscope
It is even possible to see tiny ‘grains’ or grana (singular: granum) inside the chloroplasts using light microscope
The grana inside the chloroplasts contains
Chlorophyll
What is chlorophyll
The green pigment which absorbs light during photosynthesis
What are chromatin
A highly staining material in the nucleus of which chromosomes are made, consisting of DNA, proteins and small amounts of RNA
What do chromatins look like when stained
They are visible as patches or fibres within the nucleus when stained
