4.1 Structure and Replication of the Genetic Material Flashcards
Define gene
units of inherited information that carry a code for specific traits or functions
3 main components of a DNA molecule
ring-shaped sugar(deoxyribose), phosphate group, nitrogenous base pairs
Another word for DNA sequence
codon
What does DNA stand for
Deoxyribonucleic acid
4 types of nitrogenous bases found in DNA
Guanine, cytosine, adenine, thymine
What form does a cell’s DNA take in the interphase stage
chromatin
Summarize what happens during the process of cell division in mitosis
- M phase
Mitosis: nucleus + duplicated chromosomes distributed into 2 daughter nuclei
Cytokinesis: cleavage furrow + cell plate, cytoplasm divides+ cell splits into 2 genetically identical daughter cells
Describe how a cell’s chromatin changes as the cell prepares to divide.
Interphase: chromatin
Early mitosis: chromosomes (chromatin compacted)
Late mitosis: sister chromatids (chromosome duplicated)
What is the role of interphase?
Preparing for cell division
-doubling organelles + DNA
-checks codons + base pairs (both DNA) for errors
List each phase in the cell cycle.
G1, S, G2, M(mitosis and cytokinesis)
G1 phase
-doubles organelles
-carries out metabolic processes + reg. cell activities
S phase
DNA is doubled
G2 phase
DNA(codons+base pairs) checked for errors
Explain why DNA’s structure is called the double helix.
-made of 2 long strands of DNA that are intertwined + look like a twisted ladder
List 2 human traits
Any trait…
E.g curly hair, brown eyes, straight hair
Give 3 reasons why cells divide
- Growth
- Repair
- Reproduction
How are the following terms related: DNA, chromatin, chromatid and chromosome?
-They are all different names for DNA based on how it’s packaged
-Chromatin: long, loose fibres of DNA
-Chromosome: tightly wrapped fibres of DNA
-Chromatid: duplicates to form chromosomes (for cell
division
What is the role of DNA in a cell that’s not dividing?
Interphase: DNA exists as a mass of very long fibres —->chromatin
Template strand: AGTCCG. What is the complementary strand?
TCAGGC
What is the codon in AGTCCG
AGT
Why is it necessary for a cell to replicate its DNA prior to cell division?
So that daughter cells can have a complete set of genetics/DNA
Histone vs. Nucleosome
histone proteins: proteins that help in the packaging of DNA structures
nucleosomes: basic unit of DNA packaging (8 histone proteins with DNA wrapped around it)
How many ways can the nucleotide sequence GAT be arranged?
6
What are telomeres, and how do they protect genetic information?
protective caps on the ends of chromosomes that prevent them from losing DNA
What happens when telomeres get too short?
Cells can’t divide and can cause death
What can telomeres be an indicator of?
Age and general health
How many chromosomes does a human body cell contain in the G1 phase, just before M phase and just after cytokinesis?
46
Suggest what would happen to a single-celled organism if it were to go through many rounds of mitosis but not cytokinesis.
cell keeps dividing and doubling organelles + chromosomes + nuclei = cell will explode
Suggest reasons why blood cells and skin cells reproduce more often than other cells in the body.
-constantly being lost (neurons+muscle cell rarely need to be replaced but skin cells wear out fast)
-RBCs: constantly bursting and need to be replaced (short lifespan)
-WBCs: don’t live longer than 20 day
What are pyrimidines and give two examples
single-ring structures (thymine+cytosine)
What are purines and give two examples
double-ring structures (adenine+guanine)
What is the name of the bond that links the sugar of one nucleotide to the phosphate group of the next
Phosphodiester bond
M phase meaning
Mitotic phase
Give an example of a monomer
Nucleotide because it makes up the polymer
Give an example of a polymer
DNA because it’s made up of monomers
genetics
Genetics is the study of genes, heredity, and the variation of organisms
true or false: the DNA in prokaryotes is packaged
false
trait
a characteristic of an organism (e.g. curly hair)
acquired trait
traits we acquire as we live
(e.g. knowledge)
inherited trait
traits we inherit from our parents/ancestors
(e.g. blue eyes)
what type of trait is getting cuts from falling?
acquired trait
what type of trait is flavour of fruit from different apple trees?
inherited
what type of trait is calluses on your finger?
acquired
what does DNA stand for?
deoxyribonucleic acid
DNA is organized into ______
genes
Gene
Gene is a distinct portion of a cell’s DNA.
Genes are __________ for making everything the body needs (ex. ___. )
coded instructions; proteins
genes carry the code for ________________ (E.g. Eye Colour)
specific inherited traits
______ will tell us what specific eye colour it is (e.g. BB or Bb or bb)
Alleles
DNA is made up of ______
Deoxyribose(sugars) + Nucleic acids =
Deoxyribonucleic Acid
what is the monomer in the DNA structure?
nucleotide
what is the polymer in the DNA structure?
DNA
the pyrimidines are
thymine and cytosine
the purines are
guanine and adenine
single rings are called
pyrimidines
double rings are called
purines
the single-ring pyrimidines are
cytosine and thymine
the single-ring pyrimidines are
cytosine and thymine
the double-ring purines are
guanine and adenine
Eukaryotes have 2m of DNA in their nucleus, packed into proteins called ____
histones
nucleotides are made up of…
made up of sugars + phosphates + base pairs
make a flowchart describing the structure of DNA in a cell
cell→nucleus→chromosome→nucleosomes (8 histone proteins)→histones→sugar + phosphate backbone → nucleotide→nitrogenous base pairs
segment of DNA is called
gene
chromatin
Chromatin: long fibers of DNA
Chromosome
Chromosome: condensed DNA
histone
Histone: a protein that chromatin wraps around
Nucleosome
Nucleosome: DNA + Histone packages resembling beads
8 histone proteins = _________
1 nucleosome
who discovered the structure of DNA
Watson and Crick “discovered” the double helix structure of DNA (after taking Rosalind Franklin’s data and notes) and won a Nobel Prize in 1962
what gives the DNA double helix its shape
Tight hydrogen bonds between base pairs gives the molecule its shape
what makes up the DNA double helix
Sugar-phosphate backbone
-on outside
Nitrogenous bases
-on inside
-form the “rungs” of the ladder
sugar phosphate backbone
-Backbone chemically bonds nucleotide subunits together (phosphodiester bond)
-links the sugar of one nucleotide to the phosphate group of the next
what is the bond called that links the sugar of one nucleotide to the phosphate group of the next
phosphodiester bond
what are the sugars in DNA called?
deoxyribose
nucleotides
-Each DNA molecule has thousands of these paired nucleotides arranged in a twisted, double-helix
-Join the two halves of the “ladder” together
-Each nucleotide consists of:
-nitrogenous base
-phosphate group
-pentose sugar
Different combinations of base pairs can code for different …
proteins, genes, and functions
One strand of the DNA is ___________ to the other
complementary
Nucleotide chains vary in ______ (hundreds to MILLIONS of nucleotides)
length
The number of possible nucleotide sequences is _________
unlimited
The nitrogenous bases are arranged in ______ called ______
triplets; codons
Arrangement of nucleotides in DNA stores _______
information
The genes included in DNA code for specific __________
proteins/functions
relationship between gene, trait, DNA, protein
DNA has gene in it→ gene makes protein→protein creates the characteristic trait you have
Every Eukaryotic cell undergoes a …
Cell Cycle
2 main stages in cell cycle
Composed of 2 main stages:
1.) Interphase
-growing stage
2.)Mitosis
-division stage
G1 phase
Carries out metabolic processes and performs its regular cellular activities
Increases protein supply
Creates more organelles
Grows in size
S phase
DNA is duplicated
G2 phase
replicated DNA checked for errors
M phase
Stage of cell cycle in which the cell divides
2 processes in M phase
Mitosis
Cytokinesis
mitosis
nucleus and duplicated chromosomes divide and are evenly distributed between 2 “daughter” nuclei
cytokinesis
the process by which the cytoplasm divides into 2 genetically identical daughter cells
true or false: cytokinesis usually begins BEFORE mitosis is complete
true
Each chromosome consists of 2 identical joined copies of ______________
sister chromatids
Sister chromatids are joined together by a __________
centromere
telomeres
protective caps on chromosomes
Once telomeres get too short the cell can no longer ____
divide
true or false: telomeres contain information for making proteins
false
