AND CORRECT ANSWERS
COMPREHENSIVE STUDY GUIDE
●● What is cellular differentiation?
Answer: the process by which a cell becomes specialized to perform a
specific function
●● What are somatic cells
Answer: Somatic cells are any cell in the body other than cells involved
in reproduction, they divide by mitosis
●● What are stem cells?
Answer: unspecialised cells which can divide into many types of cells
●● How many chromosomes do humans have
Answer: They have 46 chromosomes divided into 23 pairs
●● What is differentiation
Answer: The process in which an un-specialised cells becomes
specialised.
,●● What are embryonic stem cells?
Answer: Unspecialised cells that can develop into any type of cell
●● What are the differences between embryonic and tissue stem cells
Answer: Embryonic are able to divide into any type of cell so are
pluripotent.
Tissue stem cells are only able to divide into a limited amount of cells of
the same type, they are multipotent
●● Where are tissue stem cells found?
Answer: Skin or bone marrow
●● Gives examples of both cells
Answer: Tissue - bone marrow, phagocytes, lymphocytes
Embryonic - gametes
●● What can stem cells in bone marrow do?
Answer: differentiate into blood cells, platelets, phagocytes and
lymphocytes
●● What are the therapeutic and research uses of stem cells
Answer: Therapeutic- repair of damaged or diseased organs or tissues
Research- create model cells to study how diseases develop.
,●● what do somatic cells divide by?
Answer: mitosis to produce more somatic stem cells
●● What do germline cells divide by?
Answer: Mitosis then meiosis to produce haploid gamete
●● Describe the antiparallel structure
Answer: -Runs in a 3' to 5' direction and opposite on other
-has deoxyribose at the 3' and 5' at phosphate at end
●● What are chromosomes composed of?
Answer: Tightly coiled DNA and packaged with associated proteins.
●● Describe the stages of replication of DNA?
Answer: - DNA strands unwound and unzipped
- The weak hydrogen bonds are then broken
- DNA polymerase requires a primer to start replication
- DNA polymerase adds free nucleotides
- DNA polymerase can only add nucleotides in a 3' to 5' direction, cause
on to be replicated continuously and other in fragments
- Ligase then joins the completed stand.
, ●● what is a DNA polymerase
Answer: An enzyme which adds free nucleotides during DNA
replication
●● What is a primer
Answer: A primer is a short complementary strand of nucleotides which
binds to the 3' end of the template.
●● What are the stages of PCR?
Answer: Step 1 - separate the strands (92 to 98)
Step 2 - Cooled to allow primer to bind to target sequence (50-65)
Step 3 - Heated to allow heat tolerant DNA polymerase to replicate (70-
80)
●● What are the applications of PCR?
Answer: Used to amplify DNA and can be used to confirm the presence
of of individuals at crime scenes
●● What does gene expression involve?
Answer: transcription then translation.
Only a fraction of the genes in a cell are expressed.