B-1 Cells Flashcards
Nucleus
Organelle and centre of most cells (Eukaryotic) which contains genetic information.
Cytoplasm
A water based gel found in cells that most organelle are found in.
Cell membrane
The membrane around a cell that controls what comes in and out of it.
Mitochondria
The powerhouse of the cell
Where respiration takes place
Ribosome
The sight of protein synthesis in a cell
Cell wall
The structure around plant cells to make them stronger
Vacuole
Large organelles found in cells containing fluids or waste
Chloroplast
The organelles where photosynthesis takes place
Eukaryotic cells
Membrane bound organelles
Multi cellular
Mitochondria present
Prokaryotic cells
Single cells
No membrane bound organelles
No mitochondria
Plasmid
A double stranded DNA that is able to replicate chromosomal DNA
Order of magnitude
Numbers written timesed by the power of 10. Used to show the size of cells
Nerve cell adaptations
Stretched out ends.
Long body to reach other cells
Muscle cell adaptations
Allows them to communicate
Sperm cell adaptations
Long tail to swim.
Head to burrow into egg.
Root hair cells adaptations
Large surface area to speed up osmosis.
What are chromosomes
- Chromsomes contrair genetic information
- Carry a large number of genes
- Travel in pairs
Describe the stages of the cell cycle
Growth and DNA replication
- DNA is spread out along long strings
- Before it decides it increases in size and increases amount of subcelluar structures
- Then DNA is duplicated.
Mitosis
- The chromosomes are lined up at the centre of the cell and pulled apart to opposite ends
- Membranes form around the sets of chromosomes. These form the nucleus.
- Lastly the cyctoplasm and cell membrane divide
What are stem cells
- Stem cells are undifferentiated (unspecialised) cells
- They can differentiate into other form of cell dependant on the need
Where can stem cells be found
Stem cells can be found in Embryos - can specialise widely
Human bone barrow- less variety in what they can change into
What are the benefits of stem cells
- Stem cells can be used to cure diseases.
- Embryonic stem cells can be transferred to sick people e.g diabetes
- There is no risk of rejection as it adapts to people
- Can produce identical plants
What are the disadvantages of stem cells
- Some people feel human embryos should unit be used as they are potential human life
- Embryos cannot consent
- It can be very expensive
What is diffusion
- Diffusion is the spreading out of particles from an area o high concentration to low concentration across a concentration gradient
- The higher the gradient the faster the rate
- The higher the temperature the faster the rate
What type of substances can diffusion take place
- Gasses and liquids as they have free particles that can move
How do cell membranes use diffusion
- Cell membranes hold the cell together
- They also let things in and out through diffusion
- Only very small molecules can diffuse through this
- The larger the surface area of the membrane the faster the division rate
What is osmosis
- Osmosis is the moment of water across a partially permeable membrane from an area of high water concentration to an area of low water concentration
- It is a type of diffusion
What is active transport
-Active transport IS the movement of substances against a concentration gradient- using ATP energy
Why is active transport needed
- Active transport is needed as for example trees need minerals that are in lower concentrations in the soil. It has to get these through this
- Humans also need it in the gut where there is a lower concentration of nutrients but a higher concentration in the blood. We have to access this glucoseH and we do so through active transport
How does surface area to volume ratio influence rate of reactions
- The higher the surface area to volume ratio the faster the rate of reaction
- IT allows for the faster exchange of substances between organisms e.g. cells
What are some adaptations in cells to increase surface area to volume ratio and increase rate of relations between cells
- Thin cell membrane for fast diffusion
- Large surface area
- Large amounts of blood vessels
- Gas exchange surfaces
How have the alveoli in the lungs adapted for fast gas exchange
- Alveoli
- Huge surface area- 75m2- large SA/V ratio
- Moist lining for dissolving gasses
- Very thin walls
- Good blood supply
How has the Villli in the small intestine adapted for fast gas exchange
- Villi
- Increase the surface area and food is absorbed more quickly into the blood
- Millions present
_ single thin layer
_ very good blood supply
How are leaves sectored to aid fast gas exchange
- The underneath of the leaf has stomata where co2 can come through
- Oxygen and water can diffuse out of the stomata
- Guard cells can protect the stomata
- Shape allows for large SA/V ratio
- Walls of cells form another exchange surface
How hace gills on fish adapted for fast gas exchange
- Each gill has lots of thin plates called gill filaments which have large surface areas
- Gill filaments have many lamellae increasing surface area even more
- Lamellae have lots of blood capliedries
- Thin surface to allow for fast diffusion
- Concentration of oxygen always higher in water
