4.1 Structure and Replication of the Genetic Material Flashcards by Nadia Taheri

Define gene

units of inherited information that carry a code for specific traits or functions

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3 main components of a DNA molecule

ring-shaped sugar(deoxyribose), phosphate group, nitrogenous base pairs

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Another word for DNA sequence

codon

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What does DNA stand for

Deoxyribonucleic acid

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4 types of nitrogenous bases found in DNA

Guanine, cytosine, adenine, thymine

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What form does a cell’s DNA take in the interphase stage

chromatin

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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

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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)

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What is the role of interphase?

Preparing for cell division
-doubling organelles + DNA
-checks codons + base pairs (both DNA) for errors

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List each phase in the cell cycle.

G1, S, G2, M(mitosis and cytokinesis)

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G1 phase

-doubles organelles
-carries out metabolic processes + reg. cell activities

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S phase

DNA is doubled

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G2 phase

DNA(codons+base pairs) checked for errors

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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

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List 2 human traits

Any trait…
E.g curly hair, brown eyes, straight hair

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Give 3 reasons why cells divide

Growth
Repair
Reproduction

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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

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What is the role of DNA in a cell that’s not dividing?

Interphase: DNA exists as a mass of very long fibres —->chromatin

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Template strand: AGTCCG. What is the complementary strand?

TCAGGC

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What is the codon in AGTCCG

AGT

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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

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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)

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How many ways can the nucleotide sequence GAT be arranged?

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What are telomeres, and how do they protect genetic information?

protective caps on the ends of chromosomes that prevent them from losing DNA

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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?

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