2.5 Cell division Flashcards
What are the 2 main phases of the cell cycle in eukaryotic cells?
- Interphase
- Mitotic phase
What are the 3 stages of interphase?
G1
S
G2
What are the 2 stages of the mitotic phase?
- Mitosis
- Cytokinesis
How is the cell cycle controlled?
Checkpoints - G1 checkpoint, G2 checkpoint and spindle assembly checkpoint
What are the 4 stages of mitosis?
- Prophase
- Metaphase
- Anaphase
- Telophase
How many divisions does meiosis involve?
2 - Meiosis I and Meiosis II
What happens during meiosis I?
it is the reduction division when the pairs of homologous chromosomes are separated into 2 cells. Each intermediate cell will only contain one full set of genes instead of 2, so the cells are haploid
What happens during meiosis II?
similar to mitosis, and the pairs of chromatids present in each daughter cell are separated, forming two more cells. 4 haploid daughter cells are produced in total.
Name 3 examples of specialised animal cells
- Erythrocytes
- Neutrophils
- Sperm cells
Name 3 examples of specialised plant cells
- Palisade cells
- Root hair cells
- Guard cells
How are erythrocytes specialised for their function?
- biconcave shape increases surface area
- flexible to squeeze through capillaries
How are neutrophils specialised for their function?
- multi-lobed nucleus makes it easier to squeeze through small gaps to reach infection site
- granular cytoplasm contain many lysosomes
How are sperm cells specialised for their function?
- flagellum for swimming
- contain many mitochondria to supply energy required
- acrosome contains digestive enzymes to digest protective layers around the ovum
How are palisade cells specialised for their function?
- absorb light for photosynthesis
- in a rectangular box shape which can be closely packed to form a continuous layer
- thin cell walls to increase rate of CO2 diffusion
- large vacuole to maintain turgor pressure
How are root hair cells specialised for their function?
- long extensions (root hairs) to increase surface area which maximises water uptake from the soil
How are guard cells specialised for they function?
- cell wall is thicker on one side so the cell does not change symmetrically as volume changes
Name 4 examples of specialised animal tissues
- squamous epithelium
- ciliated epithelium
- cartilage
- muscle
Name the 4 main categories of tissues in animals
- nervous tissue
- epithelial tissue
- muscle tissue
- connective tissue
How is squamous epithelium specialised for its function?
- thin due to flat cells, only 1 cell thick
- it is present when rapid diffusion across a surface is essential e.g. forms the lining of the lungs
How is ciliated epithelium specialised for its function?
- cilia on the surface that move in rhythmic manner to sweep away mucus
- goblet cells release mucus to trap any unwanted particles
- lines the trachea
How is cartilage specialised for its function?
- connective tissue found in outer ear and nose
- contains fibres of collagen and elastin
- chondrocyte cells embedded in an extracellular matrix making it firm and flexible
How is muscle specialised for its function?
- different types of muscle fibres e.g. skeletal muscle fibres contain myofibrils which contain contractile proteins allowing movement
Name 3 examples of specialised plant tissues
- epidermis
- xylem tissue
- phloem tissue
How is the epidermis specialised for its function?
- closely packed cells covering the surface of plants
- usually covered by a waxy, waterproof cuticle to reduce water loss
- stomata are present which allows CO2, O2 and water vapour in and out
How is xylem tissue specialised for its function?
- composed of vessel element (elongated dead cells)
- walls are strengthened by lignin which provides structural support
How is phloem tissue specialised for its function?
- composed of columns of sieve tube cells separated by perforated walls called sieve plates allowing transport of nutrients to all parts of the plant
What is an organ?
A collection of tissues that are adapted to perform a specific function
What are the 3 types of potency in stem cells?
- Totipotent
- Pluripotent
- Multipotent
What is differentiation?
the process of a cell becoming specialised
Name 2 sources of animal stem cells
- Embryonic stem cells
2. Tissue stem cells e.g. in bone marrow
Name the source of plant stem cells
meristems
Name 3 diseases that stem cells have the potential to treat
- Heart disease
- Type 1 diabetes
- Parkinson’s disease
Name 3 areas that stem cells are already used
- burn treatment
- drug trials
- developmental biology
