B2 Flashcards
Why are new cells needed ?
New cells are needed for part of an organism to grow , to replace worn out and damaged tissue .
What do new cells need to have ?
The genes that contain the instructions to make new cells , tissue and organs
What do the chromosomes carry ?
The genes that
What are three characteristics of a gene ?
They are grouped together on chromosomes
Controls a characteristic in your body
A section of your body
How many chromosomes do you have in the nucleus of your body cells ?
46 arranged in 23 pairss
In each pair of chromosomes one is inherited from the … and the other …
The father and the mother
How do body cells divide ?
In a series of stages called the cell cycle
In adults where are the regions on the body where there is continued growth or a regular replacement of cells ?
Hair follicles , the skin , the blood and the lining of your digestive system
Explain the different stages of the cell cycle ?
Stage 1 : The cells grow bigger and carry out normal cell activities . They replicate their DNA to form two other copies of each chromosome ready for cell division . They also increase the number of sub -cellular structures like mitochondria , ribosomes and chloroplast .
Stage 2 : One set of chromosomes is pulled to each end of the dividing cell and the nucleus divides .
Stage 3 : the cytoplasm and the cell membrane also to divide to from two identical daughter cells .
What is stage 2 in the cell cycle also known as ?
Mitosis
What is a stem cell ?
A cell that is unspecialised that can become any type of cell
In animals do many types of cells become specialised very early ?
Yes
What is specialised cell ?
A cell that is set out for a specific function in the body .
What is an adult stem cell ?
A stem cell that can only form the same sort of cell
What do adult stem cells replace ?
Damaged and dead cells
Are plants able to differentiate throughout their lives ?
Yes
Where are undifferentiated cells in plants formed ?
The meristems
What is an embryonic stem cell ?
An undifferentiated stem cell in the embryo
Can you move a plant cell from one part of a plant to another ?
Yes
What is cloning ?
Producing identical offspring
In a plant how can plant clones be produced ?
They can be produced from a tiny piece of leaf tissue
What can undifferentiated plant stem cells specialise into ?
Xylem , phloem , photosynthetic and root hair cells
What is a zygote ?
When an egg and sperm cell fuse together
What is a good source of adult stem cells ?
Bone marrow
What do people with type 1 diabetes have to inject themselves with ?
Insulin
What do scientists hope to use embryonic stem cells for ?
To help people who are blind
To help people who have broken bones
What are some ethical problems with using embryonic stem cells ?
Some people believe that these embryonic stem cells are part of an embryo so therefore should not be taken out of there ,
Can an embryonic stem cell be differentiated in to any type of specialised cell ?
Yes
Why is cloning in plants good ?
Good for economical research , agriculture and disease .
What is another concern with using embryonic stem cells ?
They might cause cancer if they are used to treat people
What are two risks with using an adult stem cell ?
They might be infected with a virus and so could transfer the infections to the patient .
If stem cells from an adult are used to treat another unrelated person , they trigger an immune response
Is stem cell research expensive ?
Yes
However with stem cell research , where else can scientists get embryonic stem cells ?
In the umbilical cord blood of newborn babies and in the amniotic fluid that surrounds the fetus as it grows .
What is therapeutic cloning ?
It involves using cells from an adult to produce a cloned early embryo of themselves.
What is the process of therapeutic cloning ?
- You have an early human embryo
- A stem cell is removed from the embryo
- The stem cell is cultured , meaning that it is multiplied
- Stem cells are developed into different tissues like the spinal cord , heart , kidney and insulin producing stem cells
What can therapeutic cloning maybe cure ?
Type 1 diabetes , spinal cords , heart damage , blindness and damaged bone .
