Flashcards in B2.5 - Simple Inheritance Deck (42)
What is mitosis?
Cell division into two identical daughter cells.
How are chromosomes arranged in body cells?
Chromosomes are found as pairs.
Why do new cells need identical genetic information?
So the new cells can do the same the job.
Why do cells divide?
To allow growth and the replacement of old and damaged cells.
What is an allele?
Different forms of the same gene.
How does mitosis take place?
-A cell produces copies of the chromosomes.
-The cell divides to form two genetically identical cells.
Why is cell division restricted in adults?
Most adult cells differentiation has already occurred.
What is a stem cell?
How do plant cells differentiate?
-Cells don't differentiate until in their final position.
-Differentiation isn't permanent.
-The cell can become a different cell easily.
What is meiosis?
Cell division where the chromosome number is halved.
Why is it easy to clone plants?
-In the right conditions, a plant cell will become unspecialised.
-The cells undergo mitosis.
-The cells differentiate to form a new plant.
What does meiosis produce?
What are the stages of meiosis?
-The chromosomes are copied.
-The cell divides in two then immediately divide again.
-Four sex cells are produced with a single set of chromosomes.
Why is there variation from meiosis?
Each gamete has different genetic information. When the gametes fuse, variation is caused by the alleles.
Give an example of how stem cells can be used to treat illness.
Nerve cells can be injected into the spine to partially cure paralysis.
What are stem cells?
Give three issues with using stem cells.
-Embryonic stem cells come from aborted embryos.
-Embryonic stem cells might cause cancer.
-Making stem cells is difficult and expensive.
How did Mendel first discover inheritance?
He conducted breeding experiments with peas.
How could therapeutic cloning be used in healthcare?
A patient's stem cells could be used to grow a genetically identical organ that could replaced a damaged organ.
What are strands of DNA made of?
Four different chemical bases grouped in threes which each code for an amino acid.
What are DNA fingerprints?
Identifying unique patterns of DNA.
What does a gene do chemically?
Codes for a combination of amino acids.
How is sex determined in humans?
The sex chromosomes determine.
XX is female
XY is male
What is a dominant allele?
An allele that controls development of a characteristic when there is only one.
What is a recessive allele?
An allele that only controls a characteristic if present in both chromosomes.
What is homozygous?
An individual with two identical alleles for a characteristic.
What is a genotype?
The genetic makeup of an individual regarding a particular characteristic.
What is heterozygous?
An individual with different alleles for a characteristic.
Why is a phenotype?
The physical appearance of an individual regarding a particular characteristic.