EOY Revision (Paper 1) 🔬🦠 Flashcards
State the definition of a nucleus?
Hint: contains cell genetics.
contains the cell’s genetics (in the form of DNA), and so controls the cell’s activities
What are the 3 main reasons for needing new cells?
1) growth
2) repair
3) development
In a cell, where are proteins made?
ribosomes
State the defeniton of cytoplasm
Hint: nutrients + salts.
A jelly-like material containing nutrients and salts. (This is where chemical reactions take place)
State the role of the mitochondria
- aerobic respiration
- to release energy, for the cell to use
Are bacteria unicellular or multicellular. Also, what does unicellular mean?
1) Bacteria are unicellular
2) unicellular- only consists of a single cell
What are the adaptations that a sperm cell has? [2]
- lots of mitochondria that releases energy in respiration. This provides the energy needed for the sperm to swim to the egg.
- flagellum so the sperm cell can swim through the uterus + fallopian tube, to reach the egg.
- sperm cell is streamlined, so it can swim.
- lots of digestive enzymes, that are used to break into the egg when the sperm reaches it.
What is differentiation?
The process by which cells change to become specialised.
What are the disadvantages of using stem cells?
- requires embryonic stem cells (ethical issues)
- body can reject stem cells, because it treats them as a foreign object.
What are the risks of using stem cells in medicine?
- virus transmission
- tumor development- this is because the could divide uncontrollably
What is diffusion?
Hint: molecules
The movement of molecules from an area of a higher concentration, to an area of a lower concentration
What is osmosis?
The movement of water particles across a selectively permeable membrane, from an region of high water concentration, to a region of a low water concentration
What is active transport?
Hint: against the concentration gradient
The movement of dissolved molecules into, or out of a cell through a cell membrane, from a region of lower concentration to a higher concentration.
In active transport, the particles move against the concentration gradient by using energy that is released in respiration.
How are root hair cells adapted for their function?
Root hair cells have lots or mitochondria, to release energy needed for active transport.
Cross out the incorrect word. As organisms get larger,
Surface area: volume increases/decreases
Answer: decreases
BACTERIA VS HUMANS
Hint: include surface area + volume ratio in answer
Hint #2: include high+ low
Bacteria:
- high surface area to volume ratio
- can rely on diffusion across their surface area, to exchange everything they need.
Humans:
- Whilst in humans, they have a low surface area to volume ratio
- And humans can’t rely on diffusion + needs specialised exchange cells.
TRUE OR FALSE: Almost all larger multicellular organisms often have larger organisms, to transport substances to parts of the body that need them.
Answer: true
What is an exchange surface?
Hint: substances are exchanged over the environment
A part of an organism over which substances are exchanged over with the environment.
What are some of the features that specialised exchange surfaces have?
Hint: surface area, membrane
- permeable membrane
- large surface area : volume (to volume)
- very thin membrane
- needs a diffusion gradient.
What are the adaptations that a root hair cell has for exchanging substances?
- A root hair cell has lots of mitochondria to take in mineral ions, for active transport.
- A root hair cell has large surface area to help with efficient absorption of water + mineral ions.
