Topic 2.6 Cell division, Cell diversity and Cellular organisation Flashcards
(68 cards)
1
Q
Explain the role of mitosis and the cell cycle
A
To produce genetically identical daughter cells, facilitating cell growth, tissue repair, and asexual reproduction.
2
Q
Explain the role of checkpoints
A
Checkpoints control the three cycle stages to ensure all processes are accurately completed.
3
Q
List the three stages of the cell cycle
A
- Interphase
- Mitotic phase
- Cytokinesis
4
Q
During interphase, what happens during the G1 Phase?
A
- The cell grows in size
- Organelles duplicate
- The cell synthesises proteins necessary for DNA replication
- The cell checks for nutrients, cell growth,
growth factors, and DNA damage
5
Q
During Interphase, what happens during the S Phase?
A
- DNA replication occurs
- Two identical sets of chromosomes produced
6
Q
During Interphase, what happens during the G2 Phase?
A
- Further cell growth happens
- Cell continues to produce proteins and organelles
- Cell checks for errors in DNA replication and repairs them
- Cell prepares for mitosis ensuring all structures and ready for cell division
7
Q
During the Mitotic phase, what happens during Prophase
A
- Chromatin condenses to form visible chromosomes
- Centrioles move to opposite poles of the cell
- Centrioles from a network of proteins called microtubules
- Nuclear envelope starts to break down
8
Q
During the Mitotic phase, what happens during Metaphase?
A
- Nuclear envelope fully breaks down
- Spindle fibres attach to the centromere of the chromosome
- Once spindle fibres are attached the position the chromosomes to the metaphase to the metaphase plate equator
9
Q
During the Mitotic phase, what happens during Anaphase?
A
- Centromeres divide, separating each pair of sister chromatids
- Spindle fibres contract pulling the chromatids to opposite poles of the cell
10
Q
During the Mitotic phase, what happens during Telophase?
A
- Microtubules disappear
- A nuclear envelope forms around each sets of chromosomes
11
Q
What happens during Cytokinesis?
A
- The division of cytoplasm, resulting in two genetically identical daughter cells
12
Q
What happens to animal cells during cytokinesis?
A
The cell membrane pinches inwards to form separate cells
13
Q
What happens to plant cells during cytokinesis?
A
A new cell wall forms between the two daughter cells
14
Q
Explain the role of Meiosis.
A
The main role of meiosis is the production of haploid gametes as cells produced by meiosis have half the number of chromosomes. It is a form of cell division that gives rise to genetic variation
15
Q
Give the definition of Homologous Chromosomes
A
A pair of chromosomes (one maternal, one paternal) that have the same genes at the same loci but may have different alleles
16
Q
How is genetic variation achived?
A
- Crossing over
- Independent assortment
17
Q
List the main stages of meiosis
A
- Interphase
- Meiosis I
- Meiosis II
18
Q
What happens during interphase?
A
- DNA replication occurs during the S phase, resulting in chromosomes consisting of two identical sister chromatids joined at the centromere
- The cell also grows and prepares for division
19
Q
During Meiosis I, what happens in Prophase I?
A
- Chromosomes condense and become visible
- Homologous chromosomes pair up to form homologous pairs
- Crossing over occurs, leading to genetic recombination
- The nuclear envelope begins to break down, and spindle fibres form
20
Q
During Meiosis I, what happens in Metaphase I?
A
- Homologous pairs align along the equator of the cell
- Independent assortment occurs as homologous pairs are arranged randomly
21
Q
During Meiosis I, what happens in Anaphase I?
A
- Homologous chromosomes are pulled apart to opposite poles of the cell by spindle fibres
- The sister chromatids remain attached at their centromeres
22
Q
During Meiosis I, what happens in Telophase I?
A
- Chromosomes reach the poles, and the nuclear envelope may reform briefly
- The cell divides into two haploid daughter cells via cytokinesis
23
Q
During Meiosis II, what happens in Prophase II?
A
- Chromosomes condense again if they had decondensed
- A new spindle apparatus forms in each haploid cell
- The nuclear envelope breaks down (if it reformed)
24
Q
During Meiosis II, what happens in Metaphase II?
A
- Chromosomes (composed of sister chromatids) align at the equator of the cell
25
During Meiosis II, what happens in Anaphase II?
- The centromeres divide, and sister chromatids are pulled to opposite poles of the cell by spindle fibres
- Each separated chromatid is now considered an individual chromosome
26
During Meiosis II, what happens in Telophase II?
- Chromosomes reach the poles and decondense
- The nuclear envelope reforms around each set of chromosomes
- Cytokinesis occurs, resulting in four genetically identical haploid cells
27
What is cell specialisation in multicellular organisms?
It is the process by which cells undergo differentiation to perform specific functions efficiently, resulting in unique cell types with structures tailored to their roles.
28
What are the structural features and functions of erythrocytes (red blood cells)?
- Biconcave disc shape, increasing surface area for gas exchange
- Lack of nucleus and other organelles, maximising space for haemoglobin
- Flexible membrane to navigate through narrow capillaries
- Transports oxygen from the lungs to tissues and facilitate the return of CO2 for exhalation
29
What are adaptations and functions of neutrophils?
- Multi-lobed nucleus allowing flexibility and movement
- Abundant lysosomes containing digestive enzymes
- Engulf and digests pathogens through phagocytosis, playing a crucial role in the immune response
30
What are the structure and functions of squamous epithelial cells?
- Flat, thin, and smooth cells forming a single layer
- Provides a short diffusion path for gases and nutrients, lining surface such as alveoli in the lungs and blood vessels
31
What are the features and functions of ciliated epithelial cells?
- Columnar cells equipped with cilia on their surface
- Moves mucus and trapped particles out of the respiratory tract and assist in moving ova through oviducts
32
What are the structural and features and role of sperm cells?
- Flagellum (tail) for mobility
- Numerous mitochondria in the midpiece to supply energy for movement
- Acrosome containing enzymes to penetrate the egg cell
- Delivers male genetic material to the female ovum during fertilisation
33
What are the adaptations and role of palisade cells?
- Elongated cells densely packed with chloroplasts
- Located beneath the upper epidermis of leaves
- Primary site of photosynthesis, converting light energy into chemical energy
34
What are the structural features and function of root hair cells?
- Long, thin extensions increasing surface area
- Thin cell walls to facilitate water absorption
- Absorb water and mineral ions from the soil to support plant nutrition
35
What are the features and function of guard cells?
- Pair of kidney-shaped cells surrounding stomata
- Thick inner walls and thinner outer walls
- Regulates the opening and closing of stomata to control gas exchange and water loss in plants
36
How are cells organised in multicellular organisms to carry out complex biological functions?
In multicellular organisms, cells are organised into tissues, organs, and organ systems to carry out complex biological functions efficiently. This hierarchical structure ensures specialisation and coordination
37
What are tissues and what is their role?
Tissues are groups of similar cells working together to perform a specific function
38
What are the features and functions of squamous epithelium?
- Made up of flat, thin cells forming a smooth surface
- Provides a short diffusion pathway, found in alveoli for gas exchange and blood vessels for smooth blood flow
39
What are the features and functions of ciliated epithelium?
- Composed of column-shaped cells with cilia on their surface
- Moves mucus and trapped particles in the respiratory tract, preventing infections
- Found in the oviducts to transport eggs
40
What are the structure and functions of cartilage?
- Made up of chondrocytes embedded in a firm, flexible extracellular matrix
- Provides structural support, reduces friction at joints, and maintains the shape of structures like the ear and trachea
41
What is the structure of muscle tissue?
- Contains elongated cells (muscle fibres) that contract and relax
42
What are the types of muscle tissue?
- Skeletal muscle
- Smooth muscle
- Cardiac muscle
43
What is the function of the Skeletal Muscle?
- Voluntary, striated, responsible for movement
44
What is the function of the Smooth Muscle?
- Involuntary, non-striated, found in digestive and blood vessel walls
45
What is the function of the Cardiac Muscle
- Involuntary, striated, found in the heart to pump blood
46
What are the two types of Vascular Tissue in Plants?
- Xylem tissue
- Phloem tissue
47
What are the features and functions of xylem tissue?
- Long cylinders with open ends
- Composed of dead, hollow cells reinforced with lignin
- Produced by meristem cells
- Transports water and minerals from roots to leaves and provides structural support
48
What are the features and functions of phloem tissue?
- Tubes made up of living cells, which are involved in translocation
- Made up of sieve tube elements and companion cells
- Transports sugars (sucrose) and nutrients throughout the plant via translocation
49
What are organs and how do they function?
Organs consist of multiple tissues working together to perform a specific function
50
Give examples of organs and how do they function?
Organs consist of multiple tissues working together to perform a specific function
51
Give examples of organs and their associated tissues
- Lungs - contains squamous and ciliated epithelium for gas exchange and mucus movement
- Heart - contains muscle tissue for pumping blood
- Leaf - contains xylem, phloem, and mesophyll for photosynthesis and transport
52
What are organ systems and how do they function?
Organ systems are groups of organs that work together to perform major functions
53
What are the components of the respiratory system?
- Lungs
- Trachea
- Ciliated epithelium for gas exchange
54
What are the components of the circulatory system?
- Heart
- Blood vessels
- Muscle tissue to transport nutrients and oxygen
55
What are the components of the skeletal system?
- Bones and cartilage providing structure and protection
56
What are the components of the plant transport system?
- Xylem and phloem transport water, minerals, and sugars
57
What are stem cells and why are they important?
Stem cells are undifferentiated cells that can self-renew and differentiate. They are essential for growth, development, and tissue repair in multicellular organisms
58
What are some uses of stem cells in research and medicine?
- Repair of damaged tissues
- Treatment of neurological disorders such as Parkinson's and Alzheimer's
- Studying development
59
What is self-renewal in stem cells?
Stem cells can divide continuously to produce identical, undifferentiated cells, maintaining the stem cell pool throughout an organism's life
60
What is meant by potency in stem cells?
Potency refers to varying capacities of stem cells to differentiate into different cell types
60
What are multipotent stem cells?
Multipotent stem cells can differentiate into multiple cell types within a specific tissue
60
What are totipotent stem cells?
Totipotent stem cells can differentiate into any cell type, including extra-embryonic tissues like the placenta and umbilical cord
60
What are pluripotent stem cells?
Pluripotent stem cells can form all cell types of the developing foetus but cannot from extra-embryonic tissues
60
What is differentiation in stem cells?
Through differentiation, stem cells become specialised cells with distinct structures and functions, such as erythrocytes, neurons, or muscle cells
60
What happens during the differentiation process of stem cells?
Differentiation involves the activation and repression of specific genes within a stem cell, leading to the development of specialised structures and functions. For example, in the differentiation of erythrocytes from bone marrow stem cells, the cells change such as the loss of the nucleus and the accumulation of haemoglobin to efficiently transport oxygen
60
Explain how stem cells are used in regenerative medicine
Stem cells can be used to replace damaged or diseased tissues, offering potential treatments for conditions like Parkinson's disease, where stem cells can differentiate into dopamine-producing nerve cells in the brain
60
List the two types of application of stem cells in medicine and research
- Regenerative Medicine
- Developmental Biology Research
60
Explain how stem cells are used in developmental biology research
Studying stem cells helps scientists understand the processes of cell differentiation and tissue formation, providing insights into developmental disorders and potential therapeutic targets
