Chapter 2 🤕 Flashcards
What is mitosis?
When the genetic material in a cell is doubled and then the cell splits into two identical nuclei
What happens in stage 1 of the cell cycle?
The cells grow and increase their mass
DNA is replicated to form two sets of each chromosome
Increased numbers of mitochondria, ribosomes and chloroplasts
What happens in stage 2 of the cell cycle?
Mitosis: one set of chromosomes is pulled to each end of the dividing cell
Nucleus divides
What happens in stage 3 of the cell cycle?
The cytoplasm and cell membrane divides to form two identical daughter cells
What is a stem cell?
An unspecialised cell
When do most animal cells differentiate?
Early stage of life
What can embryonic and adult stem cells do?
Embryonic stem cells and adult stem cells can be cloned and made to differentiate into different types of cell
Examples of conditions that may be helped by stem cells
Paralysis and diabetes
Problems with embryonic stem cells
Ethical -> come from aborted embryos
Progress is slow and expensive
They grow and divide rapidly -> cancer?
How many chromosomes are in each cell’s nucleus?
46, arranged in 23 pairs
What is the cell cycle?
How body cells divide
Why is mitosis important?
Growth
Repair
Development
What is differentiation?
When a cell becomes specialised to carry out a particular job
What do adult stem cells do?
Replace cells that can’t divide like RBCs and skin cells
When can most plant cells differentiate?
All through their lives
What is cloning?
Producing identical offspring
What is a zygote?
When a sperm and egg fuse to form a single cell
What is a good source of adult stem cells?
Bone marrow
Why are stem cells used to treat various diseases?
They differentiate to form the cells needed to treat the disease
Why are stem cells important in plants?
It allows us to make large numbers of rare plants reliably and safely
What is an ethical issue of stem cells?
Embryonic stem cells come from aborted embryos
People see this as a violation of the embryos rights as they can’t consent
Economic problem with stem cells
Progress is slow, difficult and expensive
Illness problems with stem cells
Grow and divide rapidly -> cancer?
Could be infected with viruses and transfer it to patient
What is therapeutic cloning?
Using cells from an adult to produce a cloned embryo of themselves to provide embryonic cells
What are stem cells currently being researched to treat
Spinal cord injuries Diabetes Heart after a heart attack Blindness Damaged bone and cartilage
what is binary fission?
how bacteria cells divide, they split in two
in binary fission, how does a cell divide?
- duplicates DNA
- increases size and moves one set of DNA to each end of cell
- cytoplasm divides and new cell walls are made
- two daughter cells are made
what is the mean division time of a bacteria cell
the average time it takes a bacteria cell to divide into two
what is a culture medium for bacteria?
contains the foods and nutrients it needs to grow
what is differentiation?
when stem cells change to become specialised for its job
how can stem cells be used to preserve rare species of plant?
stem cells can be taken and grown to produce identical clones
where are stem cells found in plants?
the meristem - where growth occurs
what are chromosomes made from?
genes
Which stage of the cell cycle is variable?
Stage 1
