Cell Biology Flashcards
Nucleus
- Contains genetic material
2. Controls the actions of a cell
Cytoplasm
Where chemical reactions occur
Cell membrane
Controls passage of substances in and out of cells
Mitochondria
Where aerobic respiration occurs
Ribosomes
Where proteins are synthesized (protein synthesis)
Which 3 structures are found in plant but not animal cells?
- Cell wall
- Permanent Vacuole
- Chloroplast
Cell wall
- Made of cellulose
2. Strengthens the cell
Permanent Vacuole
- Filled with cell sap
2. Supports the plant
Chloroplast
- Contains Chlorophyll
2. Absorb light to make glucose through photosynthesis
Examples of Eukaryotic cells
Plant, animal and fungal cells
Examples of Prokaryotic cells
Bacterial cells
What are the 3 differences between prokaryote and eukaryote?
Prokaryotes:
- Are smaller
- do not contain mitochondia or chloroplasts
- Do not have DNA enclosed in a nucleus (Plasmids)
Plasmids
- Loops of DNA that can be transferred between cells
2. Allows bacterial cells to move genes
Flagella
Tail like structures which help bacteria cells move
Resolution
The ability to see two or more objects as seperate
Why are Electron microscopes better than light microscopes? [3]
- Passes electrons => much better resolution
- Higher magnification
- Fine detail
- Can see sub cellular structures and organelles
Formula for Magnification
Magnification= image size/ actual size
Where are genes found in a cell?
Genes are found in DNA, which build up chromosomes, found in the Nucleus of a cell
How many pairs of chromosomes do Humans have?
23 pairs
Describe the process of Mitosis
- One set of Chromosomes pulled to each end of the cell
- Nucleus divides
- Cytoplasm and Cell membranes divide to form two identical cells
Why is Mitosis important? [3]
Provides cells for:
- Growth and development of multicellular organisms
- Repairing damaged tissues
- Asexual reproduction
Stem cells
Undifferentiated cells which can divide to specialize into different types of cells
Embryonic Stem cells
- Found in human embryos
2. Can specialize into all different types of cells
Adult Stem cells
- Found in Organs and tissues such as bone marrow
2. Limited range of specializations
What is the use of Stem cells?
Treating conditions caused by cell damage, e.g. Diabetes and paralysis by replacing them
Therapeutic cloning
To get Stem cells from cloned embryos
What are the objections to Stem cell treatment?
- Ethical/ religious, e.g. lack of consent from embryo
2. Risk of viral infection transfer
Describe the sources and uses of Stem Cells in plants
- Found in Meristems
- Allow plants to make cells for growth
- Can be used to clone plants
Why are some plants cloned?
- To protect a rare species from extinction
2. Large numbers of identical crop plants with features, e.g. disease resistance can be made
Diffusion
Movement of particles from an area of high concentration to low concentration
Examples of Diffusion
Oxygen in the alveoli (high conc) to blood (low conc)
What are the 3 factors affecting rate of diffusion?
- Concentration gradient
- Temperature (high= faster)
- Surface area (large SA= faster diffusion)
Osmosis
Movement of water particles from an area of high concentration to an area of low concentration across a semi-permeable membrane
Active Transport
Movement of substances from areas of low concentration to high concentration (against the concentration gradient) using energy from respiration
Examples of Active Transport
- Allows mineral ions to be absorbed by plants
2, Root hair cells - Gut/ kidney tubules to blood
Therapeutic Cloning Method [7]
- . Human egg cell from a donor is collected
- Remove and discard the nucleus from the egg cell
- Remove a body cell from the patient and extract the nucleus
- Nucleus is placed into empty egg cell
- Cells divide by mitosis and form an embryo
- Cells will differentiate to form organs
- Organ can now be used for transplant
Disadvantages of Therapeutic Cloning
- high cost
- some cells mutate and cause tumours in patients
- extracting eggs = costly and painful
Advantages of adult stem cells
- no risk or damage to embryos
- relatively safe procedure
- adults can give consent
- more reliable technique
Advantages of embryonic stem cells
- can specialize into any type of tissue to help treat diseases
- safe cost for drug development
- painless procedure
- can grow large numbers of embryos in lab
disadvantages of adult stem cell
- risk of infection from procedure
- painful procedure
- only used to treat some diseases
disadvantages of embryonic stem cell
- no consent from embryos
- cells can grow out of control = cancer
- may be rejected by the body
- patients must takes drugs for the rest of their lives
- transfer of viral infection
Advantages of Therapeutic Cloning
- no tissue rejection
- no donor needed= no long waiting time
- potential to create organs
