B2- cell division 🧫 Flashcards
What are chromosomes?
Hint: carry genes
- chromosomes, are a thread-like structure carrying the genetic information found in the nucleus of a cell.
- chromosomes carry the genes, that contain the instruction for making new cells, [aswell as all the tissues +organs required to make an entire new person/new you]
- body cells are paired + contain two of each chrosome.
What are genes? [2]
- genes, are a small packet of information that contains a characteristic, or part of a characteristic of your body.
- [It’s a section of your DNA and is carried in a large number, by chromosomes.]
What does the term ‘DNA’ mean?
Hint: makes up chromosomes
- DNA, is the unique molecule that makes up your chrosomes
Fill in the gaps: Humans have __ chrosomes in the nuclues of your body’s cells, that are arranged in __ pairs.
Humans have 46 chrosomes in the nuclues of your body’s cells, that are arranged in 23 pairs.
Describe the stages of the cell cycle [4]
Hint: growth of sub-cellular structures and…
- cell grows, and the number of sub-cellular structures [such as ribosomes and mitochondria] are increased.
- DNA then replicates to form two copies of each chromosomes
- In mitosis, one set of chromosomes is pulled to each end of the cell. The nucleus then divides
- the cytoplasm and cell membrane divides, to form two identical (daughter) cells
Define what the term ‘Differentiation’ means
Hint: specialized, perform
- Differentiation, is the process by which cells become specialized, to perform specific functions in an organism
What is a stem cell ?
- A stem cell is an undiffereniated cell of an organism, which is capable of giving rise to many more cells of the same type
- ; a stem cell, can also differentiate, to form other types of cells.
How many pairs of chromosomes does human body cells contain?
- Human body cells contain 23 pairs of chromosomes.
What are the 3 functions of mitosis?
- [mitosis is essential for] growth and development of multicellular organisms [e.g- plants and animals]
- mitosis takes place, when an organism repairs itself [e.g- when a broken bone heals]
- mitosis also happens during asexual reproduction
What are the problems of bone marrow transplants?
Hint: compatible
- the donor has to be compatible with the patient.
- Otherwise, the white blood cells produced by the donated bone marrow, could attack the patient’s body.
- there is also another risk, that viruses can passed from the donor to the patient.
What are the problems of bone marrow transplants?
- the donor has to be compatible with the patient. Otherwise, the white blood cells produced by the donated bone marrow, could attack the patient’s body.
- there is also another risk, that viruses can passed rom the donor to the patient.
What is therapeutic cloning? [3]
Hint: embryo is produced
- therapeutic cloning, is when an embryo is produced that has the same genes from the patient.
- this means stem cells from the embryo, can be transplanted into the patient without being rejected by the patient’s immune system.
- Once inside the patient, the stem cells can differentiate to replace (faulty) cells that have stopped working correctly.
What are some conditions that could be treated by therapeutic cloning?
- paralysis or diabetes, could be treated by therapeutic cloning
- ; some people have ethical or religious objections to this procedure.
Where are stems cells found in plants?
- Located in the tips of shoots and roots [roots and buds]
- ; stem cells can be found in meristem tissue, of a plant.
Where are stems cells found in plants?
- Located in the tips of shoots and roots [roots and buds] stem cells can be found in meristem tissue, of a plant.
What can you tell me about meristem tissue?
- meristem tissue can differentiate into any type of plant tissue, at any point in the life of a plant.
What’s one difference between embryonic stem cells 🆚 adult stem cells?
- Unlike embryonic stem cells, adult stem cells can’t differentiate into any other type of cell.
What can stem cells in bone marrow, differentiate into?
- stem cells in bone marrow, can differentiate into:
- red blood cells
- white blood cells
- and, platelets.
What is diffusion?
- Diffusion is: the spreading out of particles, resulting in a net movement from an area of higher concentration, to an area of lower concentration.
What is one example of diffusion? [1]
Hint: cells are surrounded
- cells need oxygen for respiration [which is carried out by mitochondria].
- cells are surrounded by a high concentration of oxygen- because oxygen is transported in the bloodstream, from the lungs.
What could we do with meristem tissue?
- we could use meristem tissue to produce clones of plants [quickly and cheaply].
- For example, we could clone rare plants to stop them from going extinct, or we could also produce clones of crop plants for farmers that are resistant to diseases.
What is one example of diffusion? [1]
Hint: waste gas
- oxygen is used to generate energy in respiration, and this produces the waste gas: carbon dioxide.
- Therefore we have a higher concentration of carbon dioxide inside the cell, than outside so the carbon dioxide moves out of the cell by diffusion.
How is urea another example of diffusion? [1]
Hint: into the blood plasma
- urea is a waste product produced inside cells, that diffuses out of the cells, into the blood plasma.
- urea is then excreted out of the kidneys.
What is one factor that affects the rate of diffusion? [1]
- difference in concentrations [known as the concentration gradient]. The greater the concentration gradient, the faster diffusion will be.
- And the smaller the concentration gradient, the slower diffusion will be.
How can temperature affect the rate of diffusion? [1]
- temperature- the higher the temperature, the greater the rate of diffusion.
- this is because, the particles have more kinetic energy and are moving faster.
How can surface area affect the rate of diffusion? [1]
Hint: cell membrane
- another factor that affects the rate of diffusion is: the surface area of the [cell] membrane- the larger the surface area of the cell membrane, the greater the rate of diffusion.
