YR 9 - Cells and Microscopy Flashcards
what are cells?
cells are the basic unit of all forms of life
why are structural differences between cells important?
the structural differences between types of cells enables them to perform specific functions within the organism.
what controls the differences in cells?
differences in cells are controlled by genes which are found in the nucleus.
what is needed for an organism to grow?
for an organism to grow, cells must divide by mitosis producing two new identical cells.
what are the types of cells?
cells can be divided into two main parts; eukaryotic and prokaryotic
what are eukaryotic cells (eukaryotes)?
plant and animal cells are eukaryotes.
what are prokaryotic cells (prokaryotes)?
bacteria cells are types of prokaryotes.
what do eukaryotes have?
they have:
a cell membrane, cytoplasm, ribosomes, mitochondria, genetic material enclosed in a nucleus
What do prokaryotes have?
include size
• prokaryotes are much smaller in comparison to eukaryotes.
• they have cytoplasm and a cell membrane surrounded by a cell wall
where is genetic material stored in prokaryotic cells?
• their genetic material is not stored in a nucleus but is rather a single loop of DNA.
• some prokaryotes have small rings of DNA called plasmids.
what do animal cells contain?
most animal cells have:
- a cell membrane
- cytoplasm
- nucleus
- mitochondria
- ribosomes
what do plant cells contain?
plant cells have:
- a nucleus
- cytoplasm
- cell membrane
- mitochondria
- ribosomes
- cell wall
- permanent vacuole filled with cell sap
- chloroplast containing chlorophyll
what eukaryotes have a cell wall?
- what is its function
plant and algal cells have a cell wall made of cellulose, which strengthens the cell.
what is the function of the nucleus?
it contains all the genetic material that controls (and regulates) the activity of the cell
what is the function of the cell membrane?
it controls what goes in an out of the cell (holds the cell together)
what is the function of a mitochondria?
it is where aerobic respiration occurs in a cell which releases energy
what is the function of ribosomes?
to produce (synthesise) proteins (protein-synthesis)
what is the function of the cytoplasm?
it is where most chemical reactions take place (where all the organelles are kept)
what is the function of the chloroplasts?
• where photosynthesis happens which makes food for the plant.
what do chloroplast contain?
• contains a pigment called chlorophyll that absorbs the sunlight energy needed for photo-synthesis to occur
what is found in permanent vacuole?
cell sap is found in the large permanent vacuole.
what is a specialised cell?
• cells that have developed specific characteristics to carry out a particular functions
how are sperm cells adapted?
a sperm cell is adapted by having a tail which allows it to swim to the egg cell.
how are root hair cells adapted?
root hair cells are adapted by having a large surface area to allow more water and minerals to be absorbed.
where are photosynthetic cells found?
they are found on the surface of a leaf to absorb more sunlight for photosynthesis.
what is the function of xylem cells?
their function is to form xylem tubes to carry water from the roots to the leaves of a plant.
what is the function of phloem cells?
their function is to form phloem tubes which carries sugar from the leaves to all other parts of a plant.
what is cell differentiation?
the process at which dividing cells (stem cells) change their function to become specified at their job
what happens as a cell differentiates?
as a cell differentiates, it acquires different sub-cellular structures to enable it to carry out a specific function.
what are undifferentiated cells?
- what can they do
undifferentiated cells are known as stem cells and they can be cloned and made to differentiate into many different types of cells
what are the types of stem cells?
there are two types of stem cells:
- those that come from a growing embryo (embryonic stem cells)
- adult stem cells which are made in the adult bone marrow
how can stem cells be usefully used?
stem cells can be used for treatment and they may help conditions such as paralysis or diabetes
what is the function of stem cells from plant meristems?
stem cells from plant meristems are used to produce new plant clones quickly and economically.
what happens in therapeutic cloning?
in therapeutic cloning, an embryo is produced with the same gene as the patient so the stem cells produced are not rejected and may be used in medical treatment.
how are chromosomes found in body cells?
in body cells, chromosomes are found in pairs in the nucleus.
what is the cell cycle?
the cell cycle is when body cells divide in a series of stages.
what happens during the cell cycle?
during the cell cycle, the genetic material (DNA) is duplicated, which then divides into two identical nuclei in a process called mitosis
what occurs in mitosis?
in mitosis, one set of chromosomes is pulled to each end of the cell and the nucleus divides. the cytoplasm and the cell membrane then divides to form two identical cells.
where is mitosis important?
mitosis is important in growth, repair and development of multicellular organisms.
how are microscopes used?
microscopes are used to allow us to see microscopic structures in cells; they magnify them.
what are the main types of microscopes?
there are two main types of microscopes:
- the light microscope
- the electron microscope
what is the difference between a light and an electron microscope?
an electron microscope has much higher magnification and resolving power than a light microscope.
what are the main types of electron microscopes?
there are two main types of electron microscopes:
- the transmission microscope
- the scanning microscope
Define:
The resolution of a microscopy
the resolution of a microscope is the ability to distinguish between two separate points
how many metres are in a kilometre?
there are 1000 metres in a kilometre
how many millimetres are in a metre?
there are 1000 millimetres in a metre
how many micrometers are in a millimetre?
there are 1000 micrometers in a millimetre
what is the formula for magnification?
magnification = size of image / size of real object
