Unit One Flashcards
What is a somatic cell
Is every cell in the body other than the cells involved in reproduction
Where are somatic cells found
Everywhere in the body
What produces the most somatic cells
Mitosis
How many chromosomes are in a somatic cell
46
Give examples of different types of tissue that form organs (3)
Muscle tissue
Nervous tissue
Epithelial tissue
Can mutations be passed onto offspring
They cannot be passed on
What is a germline cell
Gametes sex cells
Where are germline cells found (3)
In reproductive organs
Bone marrow
Embryo
What produces more germline cells
Meiosis
How many chromosomes are in a germline cell
23
Can mutations in germline cells be passed onto offspring
Yes
Describe meiosis
•homologous chromosomes separated
•chromosomes separated into single chromatids
What is differentiation
The process by which cells become specialised by switching on and off genes
What is a gene expression
Allows a cell to carry out specialised functions
Give examples of differentiated cells
Sperm cells
Nerve cells
Red blood cells
What are stem cells
Unspecialised aromatic that can decide to make copies of themselves and/or differentiate into specialised cells
What are the different types of stem cells
Embryonic
Tissue (adult)
What is the difference between multi potent and pluripotent stem cells
Pluripotent can become any somatic cell in the body
Where do you find tissue stem cells
Bone marrow
Why can tissue stem cells not specialise into ALL types of cells
They are multi potent
What types of cells can tissue stem cells turn into (4)
Red blood cells
Phagocytes
Lymphocytes
Platelets
State two uses of stem cells
Corneal repairs
Regents ration of damaged skin
How is a cancerous tumour formed
When cancer cells divide excessively
What type of signals may fail to work on tumour
Regulatory signals
What is metastasis
When the cancerous cells get in the blood stream
What three structures make up a dna nucleotide
Phosphate
Deoxyribose sugar
Base
How does a nucleotide look
A Phosphate Circle top left connected by a line to a house shape of deoxyribose sugar on the 5 carbon which is connected to a rectangle base
In a nucleotide what are attached to the carbon 1base
Carbon 5 base
1 -base
5- phosphate
How are nucleotides held together
Though hydrogen bonds
State the stages involved in the DNA replication
DNA is unwound
hydrogen bonds between bases break to form two template strands
A primer bunds to the three end of the template DNA strand
DNA polymerase adds DNA nucleotides using complementary base pairing to the 3’end of the new DNA strand which is forming
DNA polymerase can only add DNA nucleotides in one direction
This means that the leading strand(with the 3’s at the end) is replicated continuously and the lagging strand (with 5 at the end) is replicated in fragments
Fragments of DNA are joined together by the enzyme Ligase
What are the requirements for DNA replication
Primers
DNA
ATP
Enzymes dna polymerase+ ligase
4 types of dna nucleotide
PDA4E
What is the name of the procedure used to amplify DNA
Polymerase
Chain reaction
Pcr
Requirements for DNA amplification
DNA primers,
DNA(as template),
a supply of 4nuclotides
heat tolerant DNA polymerase
PD4(HDP)
How are specific target sequences located
Primers
How is the DNA double helix separated into two strands
DNA is heated to 92-98 to seperate
How is the region of DNA replicated
Primers bind to target section of DNA end 3
nucleotides are added by DNA polymerase
Why are repeated cycles of cooling and heating used
amplify the target region of DNA
What happens when dna is heated between 92-98
Break the H bonds between bases and separated two stands
What happens when DNA is cooled between 50-65
Allows primers to bind to their complementary target sequences
What happens when the DNA is heated between70 and 80
Heat tolerant dna polymerase to replicate the region of dna
What are practical uses of pcr
Help solve crimes
Set the paternity suits
Test for viruses
Diagnose genetic disorders
What is meant by the term cell genotype
The genes that the cells have
What determines cell genotype
Alleles (DNA)
What what is meant by the cell phenotype
The physical appearance of a cell
What is meant by the term gene expression
Which genes are switched on and off
Are all genes expressed within a cell
No all of them
What controls gene expression
Nucleus
What influences gene expression
Mutagenic agents
Why are hr order of bases in DNA important
Order of amino acids
Why are the sequence of amino acids in a protein important
Because the different proteins made
State four bases found in RNA
Cytosine gamine adenine and uracil
Describe the shape of RNA
Single stranded and is composed of 4 nucleotides being phosphate- ribose sugar, 4 bases
What is the role of mRNA
Carries chemical messages from nucleus to ribosome