DNA, Chromosomes, Genes, & Proteins

DNA contains

the instructions for building an organism

the complete set of DNA is called the…

genome

Genomic DNA occurs as very long molecules called…

chromosomes

Bacteria have ______ chromosome

1 circular

Eukaryotes have many ____ chromosomes

linear

The human genome has 2 sets of….

23 chromosomes

Within the chromosomes are…

genes

What are genes?

segments of DNA that encode a protein

To survive and multiple, all cells must perform

DNA replication and Gene expression

What is DNA replication?

Making an identical copy of the DNA before cell division so that each daughter cell receives the full genome

What is gene expression?

Making proteins using the information in the genes of the DNA

The DNA molecule to be copied serves as the…

template for synthesizing the new strands

The original strands are called the…

parent stands

Each of the 2 double-stranded DNA molecules created by replicatoin have…

1 parent strand bonded to a newly synthesized strand

What is it called when 1 parent strand is bonded to a newly synthesized strand?

Semiconservative replication

Replication starts at a specific DNA sequence called the…

Origin of replication (ORI)

The enzyme DNA _____ binds to the ORI

helicase

What does helicase do?

Unwinds the DNA helix, exposing single-stranded regions

What does the single-stranded region act as

the template strand

Primases

synthesize short stretches of RNA called primers that are complementary to the exposed template

DNA Polymerase III

attaches to primer and synthesizes new DNA in the 5’-3’ direction, using one parent strand as a template to make the complement

What is the point of RNA primers?

cannot begin synthesis without the primer because DNA Pol III adds nucleotides only to an existing nucleotide strand

Gyrase

relieves the pressure built by helicase when unzipping the DNA strand

Leading strand

Synthesis of one new strand proceeds continuously as fresh template is exposed, moving the same direction as helicase

Lagging strand

proceeds the opposite direction as the helicase, so synthesis must be reinitiated many times

Each reinitation on the lagging strand requires another…

RNA primer and DNA Pol III to synthesize small fragments of DNA

Okazaki Fragments

small fragments of DNA in lagging strand

DNA Pol I removes RNA primer nucleotides and…

siultaneously replaces them with DNA nucleotides

DNA ligase

seals the gaps between fragments by forming covalent bond in the backbone between adjacent nucleotides

Flow of information

DNA → mRNA → protein

Transcription

DNA information is copied into mRNA

Translation

mRNA is used to synthesize the protein (occurs in ribosome)

3 different types of RNA required in gene expression

1. Messenger RNA

2. Ribosome RNA

3. Transfer RNA

mRNA

information intermediate between DNA and the protein

rRNA

constituent of ribosomes that catalyzes the formation of peptide bonds

tRNA

brings amino acids to ribosomes for their assembly into proteins

RNA polymerase binds to…

specific DNA sequence called the promoter

RNA Polymerase synthesizes…

complimentary mRNA from the DNA template

The binding of RNA Pol ____ a short stretch of DNA, exposing template DNA

denatures

Does RNA Polymerase require helicase?

NO!!!

RNA pol can start synthesis….

without a primer

What direction does RNA polymerase synthesize

5’ → 3’

terminator

termination of transcription at a distinct nucleotide sequence

the information that was in the ______ _____ of the DNA is now in the nucleotide sequence of _____

nucleotide sequence, mRNA

codon

set of 3 sequential mRNA nucleotides that encode one specific amino acid

what makes a protein?

strand of amino acids

The genetic code is…

universal (used by all living organisms)

How many codons are there?

64

The start codon is always…

AUG

AUG

codes for Met (always the first codon)

60 codons translate the remaining…

19 amino acids

There are 3 _____ codons which signal the end of translation

stop

mRNA is read in groups of…

3 nucleotides

reading frames

dividing a nucleotide sequence (DNA or RNA) into a set of consecutive, non-overlapping three-letter units called codons

Translating a different reading frame produces…

a very different usually nonfunctional protein because of mutations

tRNA brings the…

amino acids to the ribosome

each tRNA has an ____, a group of ____ nucleotides _____ to the _____ in the mRNA

anticodon, 3, complementary, codon

Where does the ribosome begin?

start codon

What does the ribosome add?

one amino acid per codon

What bond is formed between each amino acid

peptide bonds

The ribosome moves down the mRNA in groups of…

3 nucleotides (a codon), synthesizing the protein

Stop codon

translation ends

T/F: ATP directly powers most cellular reactions, like muscle contraction

True

T/F: Chemotrophs get their energy from the sun

False - those are phototrophs

T/F: Anabolic and catabolic reactions are usually coupled together in living organisms

True

What evidence is there that glycolysis is an ancient evolutionary pathway?

No oxygen is used & is highly conserved

Where does cellular respiration occur in eukaryotes?

Mitochondria

Possible terminal electron acceptors that use an ETC

nitrate or sulfate

By what process does CO2 and O2 move across the membrane?

simple diffusion

Where does the CO2 we breathe out come from?

The pryuvate being oxidized

What happens to pyruvate before it enters the TCA?

oxidizes to become acetyl-CoA

Hydrogens get pumped out of the cell to create….

an electrochemical gradient

What does glucose become in aerobic respiration?

2 pyruvates & ATP after glycolysis

Products of glycolysis

3C pyruvate + 2NADH + 2ATP

Products of TCA

2ATP + 8NADH

products after ETC

H2O

Which step produces the most ATP?

the ETC

In some species, when does fermentation occur

when the ETC is absent

Does fermentation make more or less ATP than cellular respiration?

LESS

Catabolic reactions will…

will break down complex molecules into smaller parts, releasing energy

Anabolic reactions will…

build larger molecules from smaller parts, using energy in the process

What kind of fermentation uses pyruvate at the terminal electron acceptor?

Lactic Acid

What kind of fermentation produces ethanol and CO2

Ethanol fermentation

What is the name of yeast that performs above fermentation?

saccharomyces cerevisiae

Enzymes are composed of what monomer?

amino acids

Regulatory molecules bind to the ____ site of the enzyme

allosteric

In competitive inhibitions, where does the drug bind?

The active site of the enzyme

Two strands of DNA are held together by what bonds?

hydrogen bonds that are weak and can denature

What must happen to the DNA before a bacterial cell can divide by binary fission?

DNA must be replicated

The energy to make a DNA polymer from its monomers comes from….

nucleotide molecules

Amino acids are joined together by what bonds?

peptide bonds (covalent & strong)

What enzyme makes mRNA?

RNA polymerase

What macromolecules is the template for RNA polymerase?

proteins