Bio unit 2 -quiz

Deoxyribonucleic acid

Deoxyribonucleic acid

genetic material that occurs in the chromosomes of the nucleus as well as mitochondria

Ribonucleic acid

mostly found in the cytoplasm and is used mostly for building proteins

• Some viruses use it as their genetic material

• Viruses depend on the cells of living organisms in order to survive and replicate and are therefore not considered to be living

Nucleotides composition

-A pentose sugar -A phosphate group -A nitrogenous base

Bases with 2 rings

Purines (A&G)

Bases with 1 ring

Pyrimidines (C

Adenine complementary base-pairing

Thymine

Cytosine complementary base-pairing

Guanine

Genes

sequences of nucleotides where DNA stores genetic information

mRNA

• -Synthesized from DNA in regions encoding genes

• Contains instructions for building proteins when combined with a ribosome

tRNA

• Molecules of RNA with amino acids attached

• Function is to transfer correct amino acid to growing chain of amino acid on the ribosome

RNA

• Found in ribosomes and helps with protein synthesis

Adenosine triphosphate (ATP)

• Used in cells as a source of chemical energy

Genome

Entire sequence of DNA in an organism

Universal common ancestor

Universality of the genetic code across living organisms suggests a ____________________

Why DNA has to be able to replicate accurately:

When a cell divides, the genetic code it carries can be passed to daughter cells which are required for growth, tissue repair and reproduction

composition of DNA

DNA is a polymer composed of monomers called nucleotides

What DNA strands are held together by

Hydrogen bonds between complementary base pairs

Semi-conservative

In the 2 new DNA molecules produced, 1 is old from parental DNA and 1 is newly synthesized

DNA replication is carried out by

Series of enzymes

First stage of DNA replication

Separation of double helix into two single strands

How DNA strands are separated

Enzyme helicase unwinds and breaks hydrogen bonds between complementary base pairs

DNA polymerase function DNA replication

Moves along each strand and adds complementary nucleotides

• forming covalent bonds between nucleotides creating a new strand

• Removes any incorrect nucleotides in the new strand (proofreads)

End result of DNA replication

2 daughter DNA molecules identical to parent

Amplifying DNA

When only a small sample of DNA is available, it can be copied repeatedly in a process called polymerase chain reaction to amplify the small quantity

Polymerase Chain Reaction

Lab technique that can take a small amount of DNA and make millions of copies using a thermocycler, amplifies a targeted section of DNA

Primers

Component of PCR which are single-stranded, short polymers of 15-20 nucleotides which are complementary to the nucleotides at one end of the DNA to be copied

Taq polymerase

Component of PCR from thermophilic bacteria that can withstand high temperatures and still not denature

Denaturation (PCR)

Mixture is heated to 92-98 degrees to break hydrogen bonds which hold two DNA strands together

Annealing

Mixture is cooled to 50-65° which allows primers to bind with nucleotides on both strands at the ends of the target sequence

Elongation

Taq polymerase catalyses the building of new DNA strands by extending the primers

Unique properties of a protein lie in:

Which amino acids are involved in its construction, and the sequence in which the amino acids are condensed together

Transcription

Process of synthesizing RNA from DNA

How and why DNA communicates with ribosomes

To control production of proteins by producing a code that is carried from the nucleus to the cytoplasm by RNA

How is RNA exported to the cytoplasm

As mRNA

Translation

mRNA combines with ribosomes to to synthesize a protein

Initiation

RNA polymerase attaches to the DNA sequence called the promoter which promotes the binding of DNA polymerase

Elongation

• RNA polymerase synthesizes an RNA transcript

  • Has a helicase function as it separates DNA double helix by hydrogen bonds between complementary bases

• Complementary base pairs are the same as in double strand DNA except adenine is now paired with uracil on the RNA molecule

Termination

RNA polymerase reaches a transcription terminator signal on the DNA which dislodges the RNA strand and releases polymerase

Capping

At 5’ end, a modified guanine is added at the front (Guanine Cap)

Polyadenylation

At 3’ end, many adenines are added (poly A tail)

Splicing

Segments of RNA sequences get cut out

Messenger RNA

Carries genetic message from DNA to ribosomes

Transfer RNA

Functions in the cytoplasm to carry amino acids for the ribosomes

Ribosomal RNA

Combines with ribosomal proteins to construct the cytoplasmic ribosomes

Ribosome composition

Two halves, a large subunit which has binding sites for the tRNAs and catalyzes peptide bonds between amino acids, and small subunit which binds to the mRNA

Genetic code

Set of rules by which information encoded in mRNA sequences are converted into proteins by living cells

Genetic code is universal

All living organisms share the same code with a few exceptions- allows us to insert genes from one species to another using genetic engineering techniques

Coding region always starts with :

Start codon

Coding region stops with:

Stop codon

Stop codons

Blank tRNAs which do not code for an amino acid, causing the release of the polypeptide from the ribosome because there is no peptide bond to be catalyzed

Translation depends on:

Complementary base pairing between mRNA codons and tRNA anticodons

Sickle Cell anemia

Blood disorder where RBCs become sickle shaped and can’t carry oxygen properly

Why sickle cell anemia occurs

a single base substitution mutation in one of the genes that make hemoglobin. a point mutation happens in a triplet Imran codes for amino acid glutamic acid and changes it to valine

Cellular respiration

Process where energy is made available from nutrients, where there is a controlled release of energy from organic compounds in cells.

Cellular respiration changes energy from:

One form of currency (glucose) to another (atp)

Why energy needs to be turned into atp

Glucose is stable while ATP breaks down to release energy it stores

why ATP is unstable

ATP has three phosphates linked in a linear sequence, and the last two phosphates are attached by high energy covalent bonds. The negative charge of the phosphate groups repel creating unstable covalent bonds which can easily be broken by hydrolysis and hydrolysis results in release of energy.

How ATP must be produced

Continually

What ATP is synthesized from

ADP and phosphate

What does breakdown of glucose in cellular respiration do

Drives the synthesis of ATP

Aerobic respiration

Cyclic series of chemical reactions in which glucose is broken down in the presence of oxygen to produce ATP

Word equation of aerobic respiration

glucose + oxygen ➡ carbon dioxide + water + ATP

a glucose can yield a maximum of this many ATP molecules in aerobic respiration

38

Where aerobic respiration occurs

Cytoplasm and mitochondria

Number of ATP in aerobic respiration

2 needed to begin, 4 produced, net 2

Anaerobic respiration

glucose can be broken down without using oxygen to yield a small quantity of ATP

Where anaerobic respiration occurs

Cytoplasm

when anaerobic respiration is useful

• Rapid burst of ATP production needed

• Oxygen supplies run out in respiring cells

• In environments that are oxygen deficient

Fermentation

Breakdown of organic molecules for anaerobic ATP production

Word equation for anaerobic respiration

glucose ➡ lactate + ATP

Temperature as a limiting factor

Temperatures above and below the optimal temperature will decrease the rate

Carbon dioxide concentration as a limiting factor

Increases in carbon dioxide will decrease the rate of respiration

Oxygen concentration as a limiting factor

Lower oxygen concentrations will decrease the rate of respiration

Glucose concentration as a limiting factor

Low glucose levels will decrease the rate of respiration

Type of cell as a limiting factor

Some types of cells require more energy than others

Photosynthesis

Metabolic pathway in which CO2 and water are used to produce carbohydrates through a complex series of reactions.

What happens to carbon during photosynthesis

Carbon is fixed from carbon dioxide and is used to produce glucose

Where photosynthesis occurs

In chloroplasts of plant cells

How oxygen gas is produced in photosynthesis

From the photolysis of water

wavelength with higher energy

Shorter wavelength

Wavelength with lower energy

Longer

What determines the capacity for plants and more to absorb light energy

The pigments present on the chloroplast membranes

What varies in each photosynthetic pigment

How much of each wavelength of light is absorbed

What happens when light is absorbed in a pigment

It is used to raise an electron in the pigment to a higher energy level which requires a specific quantum of energy. This high energy level leads to the creation of chemical bonds.

Action spectra

Indicates rate of photosynthesis at different wavelengths of light, can be calculated from rate of oxygen produced or rate of carbon dioxide used.

Chromatography

Separates photosynthetic pigments based on their solubility in an organic solvent

Photosynthesis limiting factors

• Amount of water

• Amount of sunlight

• Temperature

• Carbon dioxide

• Chloroplasts

• Chlorophyll