Cell division and inheritance. Flashcards
characteristics are passed on from one…..
generation to the next.
Organisms that adopt the characteristics of previous generations are
Plants and animals.
The scientist that proposed the idea of genetics
Mendel.
The capitol letter in a genetics diagram usually represents
The dominant gene.
The lower case letter in a genetics diagram usually represents
The recessive gene.
Tt is called a
geneotype.
What type is the organism if it has the same alleles?
Homozygous.
Different alleles?
Hetrozygous.
what is the expression for the gene outcome?
Phenotype
Two types of cell division
Mitosis and meiosis.
Cells that contain the genetic information
Chromosomes.
Stages of mitosis
Separate nucleus has elongated strands of DNA. The DNA is copied to form an ‘x’ shape. The chromosomes line up in the center of the cell and are pulled apart to make two identical sets. The two sets are enclosed in their own membrane forming two identical cells.
What actually occurs in mitosis?
Copies of a cells genetic material is made.
Mitosis occurs during…
Growth or to produce replacement cells to replace damaged ones.
How many sets of chromosomes do body cells have?
two.
How many sets of chromosomes do gamete cells have?
one.
Gamete cells are basically
sex cells.
Describe meiosis.
You start with a diploid cell(DNA already copied) the chromosomes line up in the center of the cell. The pair of chromosomes are pulled apart to form two nuclei in the same cell.The two cells then divide with each HAPLOID cell having a single set of chromosomes form in the 2nd cell division.
How many human haploid cells do gamete cells contain?
23.
How many chromosomes does the fertilized cell have?
46(23 pairs)
Define deffrentiate
When something becomes different in the process of development.
Type of cell that can differentiate into many types of cells
Stem cells.
Where can stem cells be found?
Bone marrow or in early human embryos.
Cells for specific functions(skin, organ tissue etc) are made in the process of…
Differentiation.
Why is bone marrow not as effective for stem cell use?
The stem cells inside can only be used for a few specific cell types.
three cells bone marrow stem cells produce
red blood cells(carry oxygen around the body), white blood cells(help fight infection) and platelets(help stop bleeding).
Stem cells from embryo’s can form(two)
New nerve connections and cardiac tissue for people suffering heart disease.
Why is stem cell research controversial?
Ethnic issues with using embryo’s(potential life).
Potential life vs. seriously ill living people.
It’s allowed in some countries, like the UK, but there’s a strict guideline of how it can be carried out.
What chromosomes do men have?
An ‘X’ and a ‘Y’.
What chromosomes do women have?
Two ‘X’.
Explain amniocentesis
Parents with the possibility their child will have a disorder(due to recessive or dominant alleles) can have an injection into the womb(foetus) to gather amniotic fluid. The fluid can be tested and checked for disorders. However there’s a 1 in 100 chance of miscarriage due to the needle.
Explain PGD
Multiple eggs are taken from a woman and fertilised outside her womb. They’re checked for mutations and the healthy ones are injected back into the uterus.
Sex chromosomes females have
XX
Sex chromosomes makes have
XY
