cell biology (seneca) Flashcards
Eukaryotic cells are found in
plants, animals, fungi and protists (single-celled organisms that don’t fit other categories).
what are protists?
Eukaryotic single celled cells that are not plants, animals, fungi
Eukaryotic are —- micrometres in size.
10 - 100
Prokaryotic cells are —– micrometres in size.
0.1 - 5.0
prokaryotes are
Bacteria
what is the micrometer unit
µm
Some prokaryotic cells contain small rings of DNA called …
plasmids.
Plasmids can ——- and move between …
- replicate
- cells so that genetic information can be shared.
Prokaryotic cells do not have a (n)…
nucleus (where DNA is stored).
Most of prokaryotic cells genetic material is stored in a ——- in the …
single DNA loop
cytoplasm (watery jelly that fills the cell).
Prokaryotic cells do NOT contain (m)…
mitochondria (where respiration takes place) or chloroplasts (where photosynthesis takes place).
The cell membrane is ——— permeable
selectively
Something that is selectively permeable can …
control which substances move through it.
To multiply numbers in standard form:
- Multiply the leading numbers.
- Add the powers.
- Change into the correct format.
To divide numbers in standard form:
- Divide the leading numbers.
- Subtract the powers.
- Change into the correct format
1 µm = — m
0.000001m
1 nm = —- m
0.000000001 m
An animal cell contains the following sub-cellular structures:
- Cell membrane
- Nucleus
- Ribosomes
- Mitochondria
- Cytoplasm
The nucleus contains …
chromosomes (which contain the cell’s genetic material).
Ribosomes are responsible for …
synthesising (making) proteins.
Mitochondria is where …
aerobic respiration takes place.
Cytoplasm is a ———————- where…
jelly-like fluid that fills the cell.
most of the cell’s chemical reactions take place.
An animal cell contains a ———————– membrane.
partially permeable
As well as the sub-cellular structures that animal cells have, a typical plant cell has a few more:
- Permanent vacuole
- Chloroplasts
- Cell wall
A permanent vacuole is a …
fluid-filled sac that stores water.
Permanent vacuole is enclosed in a …
membrane (a wall that substances can pass through).
Permanent vacuole can make up as much as — of a plant cell’s volume.
90%
Chloroplasts contain ———, which is needed for the process of …
chlorophyll
photosynthesis.
The cell wall ———- and is made of …
surrounds the cell
cellulose.
The cell wall —— the structural strength of the cell.
increases
When cells differentiate, they acquire ——-
different sub-cellular structures.
Many plant cells can differentiate —————
This means that plants are …
throughout their lives.
always able to create new tissues.
Most animal cells differentiate —– on in their development.
early
In mature animals, cells mostly ——————————- to replace cells and repair tissues that are already present.
New tissues are rarely created by …
divide (one cell splits to create two cells)
cell differentiation
The cytoplasm is where …
most of the cell’s chemical reactions take place
Plasmids are …
small rings of DNA.
Some bacteria have (f) …
flagella.
Flagella are …
whip-like structures used for movement.
Plasmids can replicate (have copies made) and move …
between cells so that genetic information can be shared.
Prokaryotic cells do NOT contain …
nucleus, mitochondria (where respiration takes place) or chloroplasts (where photosynthesis takes place).
Cell differentiation is the process where …
a cell develops new sub-cellular structures (structures inside a cell) to let it perform a specific function.
Differentiation happens primarily during an organism’s …
development.
The ————– is used for the cell’s motion. This allows sperm cells to travel towards the egg cell.
flagellum (‘tail’)
The —— contains the sperm cell’s nucleus. The nucleus carries one half of an organism’s genetic material.
‘head’
Sperm combines with the …
egg cell’s half of genetic material to fertilise the egg cell.
The middle section of the sperm is filled with …
mitochondria to provide the sperm with the energy it needs to travel a long distance to reach the egg cell.
Digestive enzymes are found at the tip of the head of sperm cells in the …
acrosomes.
Sperm cells spin their tails in a ——— to move themselves towards their target - the egg.
corkscrew motion
Nerve cells (or neurones) are specialised to …
transmit electrical messages around the body
What is an axon
Part of the cell that electrical signals travel along.
Nerve cells have a ——— axon. This increases …
long
the distance that electrical signals can travel.
A sheath made of a material called myelin surrounds the axon of the nerve cell. This stops the electrical nerve signals leaking out of the nerve cell.
This increases …
the speed of transmission (travel) of electrical signals.
A sheath made of a material called ——- surrounds the axon of the nerve cell. This stops the electrical nerve signals leaking out of the nerve cell.
This increases the speed of transmission (travel) of electrical signals.
myelin
A sheath made of a material called myelin surrounds the axon of the nerve cell. This stops the …
This increases the speed of transmission (travel) of electrical signals.
electrical nerve signals leaking out of the nerve cell.
What are dendrites?
Branches of a nerve cell.
Several dendrites spread outwards from the cell body to…
transfer electrical messages to other neurons
Signals are transmitted across gaps between nerve cells. What are these gaps called?
Synapses
Muscle cells are specialised (perform a specific function). They can produce …
force and motion.
- within the cell can 2. , allowing the muscle to move.
- Protein fibres
- contract
A muscle cell contains lots of —————- to generate lots of energy for motion.
mitochondria
Root hair cells are specialised (to perform a specific function). Their structure allows the plant to 1. . They also allow a plant to …
- absorb more water
take in the minerals it needs to survive.
Root hair cells cells are located underground.
This means that they do not contain …
chloroplasts (there is no light for photosynthesis).
Root hair cells have long projections that ——————- that the plant can use to absorb water and minerals.
increase the surface area
The xylem is specialised to …
transport water up the stem of a plant and into the leaves.
Xylem vessels are made up of a …
series of connected dead xylem cells.
The end walls of the dead xylem cells are …
broken to allow water to move through
—— (a substance) strengthens the cell walls of xylem cells.
Lignin
Lignin (a substance) ———————— of xylem cells.
strengthens the cell walls
The phloem is specialised to —————————————-. Phloem vessels are made up of columns of living cells.
transport food products to parts of the plant where they are needed
The phloem is specialised to transport food products to parts of the plant where they are needed. Phloem vessels are made up of …
columns of living cells.
The end walls of ———- contain small holes to allow food products to move up and down the phloem vessels throughout the plant.
phloem cells
The end walls of phloem cells contain small holes to allow …
food products to move up and down the phloem vessels throughout the plant.