- total genetic makeup in cell (can mean genotype) - all the cells DNA - all viruses' DNA or RNA

Chapter 4: Genes Flashcards by Krista Kowiak

what is genetics?

the study of heredity

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what is heredity?

passing on characteristics (traits) from parents to offspring so offspring resemble parents and eachother

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list 4 microbial traits

) shape and structure (morphology)
) biochemical reactions (metabolism)
) movement and behavior
) interactions with other organisms (pathogenesis)

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what is phenotype?

actual, expressed properties or characteristics (traits)

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what is genotype?

organisms genetic makeup (total collection of genes)

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what is genome?

total genetic makeup in cell (can mean genotype)
all the cells DNA
all viruses’ DNA or RNA

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what is environment?

any factor affecting the expression of a phenotype other than genes

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__________+_________—>___________-

genotype + environment–>phenotype

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the functional unit of genetic information is the _____

gene

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describe what genes are the 4 things they encode for

Segment of DNA in cells (or either RNA or DNA in viruses) which contained the coded information that determines:

) the sequence of mRNA which determines the primary structure of a given polypeptide (coding or structural genes)
) the sequence for rRNA (ribosomal RNA genes)
) the sequence for tRNA (transfer RNA)
) the sequence of regular RNA

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are genes in cells single stranded DNA or double stranded

double stranded (ds) DNA

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what is the flow of biological information

Genes (genotype)–> mRNA and other RNA–> polypeptide primary sequence–>proteins (enzymes)–> regulates cell chemistry–>determines cell/viral morphology and physiology (phenotype)
(slide 7)

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DNA is a polymer of what?
RNA is a polymer of what?
what links these together?

DNA-deoxyribonucleotides
RNA-ribonucleotides
phosphodiester bonds

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DNA and RNA differ in (2 things)

the nitrogenous bases they contain

the sugars they contain

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describe DNA structure (6)

-polymer is deoxyribonucleotides
-bases are adenine, guanine, cytosine, and thymine
-sugar is deoxyribose
-adenine (purine) and thymine (pyrimidine) pair by 2 hydrogen bonds
-guanine (purine) and cytosine (pyrimidine) pair by 3 hydrogen bonds
-in all cells, DNA molecule is a double stranded helix
(slides 14-17; 17 is a video)

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slide 13

information about DNA length

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describe RNA structure (5)

polymer is ribonucleotides
sugar is ribose
bases are adenine, guanine, cytosine, and uracil
phosphodiester bonds
In cells, Most RNA molecules are single stranded; some double stranded or have double strand regions

Three different types of RNA exist which may differ from each other in function, site of synthesis, and in structure. What are they?

messenger RNA (mRNA)
ribosomal RNA (rRNA)
transfer RNA (tRNA)

describe viral genomes (8)

Either DNA or RNA in same virus particle, not both
DNA or RNA can be single stranded (ss) or double stranded (ds)
Viral nucleic acid had very little or no protein associated with it
Viral nucleic acid can be linear or circular
Viral genomes may consist of 1 piece of nucleic acid or several (ie, Influenza virus had 8 pieces ss RNA)
Most viral genomes have between about 20 and 100 genes (some larger exceptions)
Viral genomes consist of between 20,000 and 100,000 nucleotides
Viral genomes are packed within a protein coat called the capsid

describe prokaryotic genomes (7)

Always composed of ds DNA
ds DNA has only a little protein associated with it
Bacterial chromosome is about 98% ds DNA and 2% protein
Most DNA is circular and supercoiled; some linear
Most have a single piece of DNA as their bacterial chromosome; but some have 2 or more
Prokaryotes have between about 2000 – 5000 genes
Prokaryote genomes are between 2 million and 5 million nucleotides

what are plasmids? about how many genes?

Small pieces of open circular ds DNA in the cytoplasm

- Found in many prokaryotes; between 5 – 50 genes

slides 23 and 24

pictures of super coiled DNA

describe eukaryotic genomes (6)

Always composed of ds DNA
Mostly linear; some circular
DNA spread over many eukaryotic chromosomes
Most eukaryotes have several chromosomes
All members of same species have same number of chromosomes (called species number or chromosome number)
Eukaryotic chromosomes are structures for organizing a lot of DNA in a little volume

each eukaryotic chromosome consists of (3 things)

) 34-35% ds DNA
) ~1% RNA
) 64-65% proteins (histones and non histones)

Eukaryotic chromosomes can exist in several types of packing. Describe (2)

-During non dividing times (interphase), they are the most loosely packed (decondensed); at this time, the individual chromosomes exist but are not visible and they are referred to as chromatin -During mitosis or meiosis, the chromosomes condense and become more tightly packed; they are also visible as individual chromosomes at this time (slide 28)

what are the 5 levels or eukaryotic chromosome structure?

1.) ds (naked) DNA- 2nm 2.) nucleosomes- 10nm (held together by histone proteins) 3.) solenoids- 30nm (held together by histone and non histone proteins) 4.) 300nm fibers- supercoils (held together by non histone proteins) 5.) higher levels- only occur during cell division (slide 30 and 31)

what is DNA replication? (2)

-Complex process involving numerous proteins which help ensure accuracy -The 2 strands separate, each serving as a template for synthesis of a complementary strand (slides 33 and 34; 34 is video)

slides 35-39

35: weird information to make into card; look at 36: picture 37: video 38: more weird info to make into card 39: table

name and describe the 5 materials required for DNA synthesis/replication

slides 40-42

describe DNA replication

44-47 and in purple notebook

describe replication machinery (2)

- DNA polymerase catalyzes synthesis of complementary strand of DNA - DNA synthesis in 5’ to 3’ direction forming phosphodiester bonds

replication machinery enzymes require what 3 things?

1. ) a template – directs synthesis of complementary strand 2. ) a primer – DNA or RNA strand 3. ) dNTPs (dATP, DTTP, DCTP, dGTP) – deoxynucleotide triphosphates

slide 51

E. Coli replication?

describe DNA gyrase (2)

- topoisomerase | - also introduces negative supercoiling to help compact bacterial chromosome

describe primase

synthesizes short complementary strands of RNA (~10 nucleotides) to serve as primers needed by DNA polymerase

DNA ligase forms a ________________ between 3’-_________ of the growing strand and the 5’-_________ of an Okazaki fragment

phosphodiester bond; hydroxyl;phosphate | slide 54-56

describe proofreading (3)

-Carried out by DNA polymerase III -Removal of mismatched base from 3’ end of growing strand by exonuclease activity of enzyme -This activity is not 100% efficient (57-58)

slide 59

E Coli?

Telomerase is an enzyme found in eukaryotes that can do what?

synthesize DNA using an RNA template and an internal RNA template thus solving the “end” replication problem

describe the end replication problem and how this is solved in euks and bacteria

-shortening of chromosomes after each round of replication -solved in eukaryotes by telomerase enzyme -solved in bacteria by disguising the ends of the linear chromosome (61-62)

describe accuracy of DNA replication

last slide :)