Chapter 6- Cell Division Flashcards
How does yeast undergo cell division?
Budding
How does fungus undergo cell division?
Budding
How does bacteria undergo cell division?
Binary fission
Do fungi have nuclei?
Yes
What is the cell wall of fungus made of?
Chitin
What is the cell wall of bacteria made of?
Peptidoglycan
What features would not be found in xylem vessels that are present in undifferentiated plant cells?
- no nucleus
- no cytoplasm
- no end walls
How does the cell wall of a xylem vessel differ from undifferentiated plant cells?
- thicker
- lignified
- contain pits
Membran elf X specially adapted for communication. how?
Has glycoproteins for (chemical released)
Where does growth in a trunk or stem come from and where is it situated?
-cambium which is situated between the xylem +phloem tissues
Why branches growing from a position just under bark of cut surface of tree?
- this is where cambium is found
- mitosis occurs in cambium
Where does growth occur in plants?
- cambium
- tip of shoot
- tip of root
- meristem
- bud
State the stage in which independent assortment occurs
Metaphase I
Metaphase II
State the stage in which formation of spindle apparatus occurs
Prophase I
Prophase II
State the stage in which separation of sister chromatids occurs
Anaphase II
State the stage in which formation of nuclear membranes occurs
Telophase I
Telophase II
State the stage in which chromosomes pulled to opposite poles occurs
Anaphase I
Why meiosis needs to have twice as many stages as mitosis?
- to halve the chromosome no.
- to separate homologous pair + sister chromatids
What feature of the DNA molecule is changed due to a mutation?
Base sequence
Effects mutation can have on structure + function of protein?
- diff primary structure
- protein shorter due to deletion or stop codon
- protein longer due to insertion/ duplication
- protein unchanged due to silent mutation
Ways in which genetic variation produced, including role of nuclear division?
- independent assortment of homologous chromosomes
- independent assortment of sister chromatids
- crossing over
- mutation
How crossing over causes genetic variation, including role of nuclear division?
- in prophase I of meiosis I
- forms chiasmata
- so chromatids will have new combination of alleles
How does independent assortment of homologous chromosomes cause genetic variation including role of nuclear division?
- in metaphase I of meiosis I
- so homologous chromosomes come from different pairs
How does independent assortment of sister chromatids cause genetic variation including role of nuclear division?
- in metaphase II in meiosis II
- produces large no. Of allele combination
How do mutations cause genetic variation including the role of nuclear division?
- mutation changes the DNA base sequence
- DNA checks did not recognise damage
- change in amino acid sequence + primary structure
How cells in multicellular organisms are organised?
- cells differentiate
- cells form tissues
- tissues form organs
- organs form organ systems
- organ systems work together
- e.g. digestive system
Type of cell division that occurs in asexual reproduction?
Mitosis
Why does the genetic material replicate before division of nucleus?
- cells are genetically identical
- so each daughter cell receives full copy of DNA
What is a homologous pair of chromosomes?
- one maternal + one paternal
- carry same genes at same loci
- carry both same and diff alleles
- centromere in same position
- pair up in meiosis to form bivalent
Types of epithelial tissue found in lungs?
- ciliated
- squamous
What is a tissue?
-a group of specialised cells that work together to complete a function
Function of squamous epithelium and where it’s found?
- short diffusion pathway as only one cell thick
- alveoli
Function on ciliated epithelium and where it’s found?
- secrete mucus + move mucus away from lungs
- trachea
Student observes the cells in stained meristematic tissue + counts how many can be seen in diff stages of the cell cycle. Why did it need to be stained?
- staining provides contrast between cell structures because diff structures take up diff amounts of stain
- chromosomes can be seen
- determined diff stages of cell cycle
Ways in which products of meiosis are diff from products of mitosis?
- not genetically identical
- 4 daughter cells produced
- they are gametes
- one set of chromosomes (haploid)
- contain half genetic info
Ways cell division in plants differs from animals?
- cell plate forms between new cells
- only occurs in meristem
- no centrioles
Processes that happen in G1 and G2?
- cell increases in size
- organelles replicate
- protein synthesis
What happens during interphase?
- generic material copied
- checking genetic material for errors
- protein synthesis
- organelles replicate
- ATP production
- increase in cell size
Why lungs can be considered an organ?
- an organ is a group of tissues that work together to perform a function
- lungs have many diff tissues inc epithelium, smooth muscle, elastic, that work together to carry out a function
What cellular structure is associated with movement of cilia?
Cytoskeleton
During stage S, genetic info is copied and checked. What would happen if not checked?
- could be a mutation
- could be an error in copying
- faulty DNA produced
- daughter cells will not receive identical genetic information
- proteins could function differently
What is a stem cell?
-undifferentiated cell that has the ability to specialise + become other cell types
Why mitosis is important to organisms?
- growth
- repair
- asexual reproduction
Adv of using umbilical cord stem cells instead of bone marrow stem cells in procedures?
- greater availability of umbilical cord stem cells so more likely to find donors
- easier to harvest
- cells at earlier stage of development
- can be stored for future
Cancer treatments can pnot differentiate between tumour cells + healthy cells. Why are tumour cells more affected?
-tumour cells divide faster than healthy cells
What 2 enzymes are used in DNA replication + what are their roles?
- DNA helicase. Breaks the H bonds between the bases of the 2 DNA strands
- DNA polymerase. Forms phospodiester bonds between adjacent nucleotides to form sugar phosphate backbone
What is meant by semi conservative replication?
- the two original strands of DNA act as templates for the new strands to form
- in the 2 molecules of DNA formed, each has a conserved original stand + a new strand
Describe prophase?
- chromosomes condense
- nuclear envelope breaks down
- centrioles move to opposite poles of cells
Describe metaphase?
- chromosomes line up along equator of cell
- spindle fibres from centrioles attach to centromeres
Describe anaphase?
- centromere divides
- spindle fibres contract pulling chromatids to opposite poles
Describe telophase?
- chromatids reach poles
- nuclear envelope reforms
At what stage in mitosis, do you change the terminology from chromosomes to chromatids?
ANAPHASE
Why genetical material must replicated before division?
- cells genetically identical
- each daughter cell receives full copy
Homologous pair of chromosomes?
-one maternal and one paternal
-carry same genes
-centromere in same position
-pair up in meiosis and form bivalent
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