Molec Cell Chapters 1 & 2 Smartwork

Organisms that have inherited their genetic instructions from a common ancestor share the same DNA sequence. True or false?

False

Which are the function of proteins?

• encasing certain viruses

• catalyzing biochemical reactions

• providing cells with structural support

• acting as molecular motors

Which is not a function of proteins?

encoding genetic information

Genetic changes followed by selection are best described as the fundamentals of what process?

evolution

What statement represents cell theory?

all cells are formed by the growth and division of existing cells

An organism that can survive life in a hydrothermal vent at the bottom of the ocean can thrive anywhere. True or false?

false

Antibiotics tend to target features that are unique to bacterial cells and absent from eukaryotic cells such as our own. What would present a safe target for a new antibiotic?

cell wall

One thing all cells have in common is an ability to colonize any environment on Earth. True or false?

false

What are prokaryotes?

archaea and bacteria

What do eukaryotic cells have that prokaryotes lack?

a nucleus and membrane-bound organelles

What cellular features unique to eukaryotes would you focus on if youre studying how eukaryotic cells obtained unique features during their evolution from a prokaryotic ancestor?

• the nucleus

• mitochondria

What is not evidence for the endosymbiotic origins of mitochondria and chloroplasts?

mitochondria and chloroplasts have similar DNA

Mitochondria and chloroplasts are each

surrounded by a double membrane

Mitochondria and chloroplasts reproduce by

dividing in two

Mitochondria and chloroplasts contain

their own DNA

Mitochondria and chloroplasts resemble

bacteria

Mitochondria are essentially the same in

all eukaryotes, including plants, animals, and fungi

How were mitochondria most likely aquired?

by an ancestral eukaryotic cell before the lines that led to animal cells, plant cells, and fungi diverged

What is the name of the process by which eukaryotic cells engulf material captured from an external medium?

endocytosis

Which structure or process mediates the exchange of materials between the endoplasmic reticulum, Golgi apparatus, the lysosomes, and the outside of the cell?

transport vesicles

What is not true of chloroplasts?

chloroplasts are present in essentially all eukaryotic cells and in certain photosynthetic bacteria

Chloroplasts have an

internal stack of membranes and is enclosed by two membranes

Chloroplasts absorb light and

generate oxygen and carbohydrate

Chloroplasts contain

their own DNA

Chloroplasts are thought to have

originated from bacteria

Self-replication of living cells occurs through the catalytic action of

proteins

The genes in the genome of an adult organism

are expressed or silences depending on whether a gene is needed in that cell type and environment

The defining property that differentiates prokaryotic cells from eukaryotic cells is their

lack of nucleus

One piece of evidence indicating that chloroplasts evolved from engulfed photosynthetic bacteria is

that they contain their own DNA

Which modern macromolecules may by relics of the hypothesized RNA world?

• ribosome

• spliceosome

Which biochemical reaction is catalyzed by a ribozyme?

peptide bond formation in protein synthesis

Which type of molecule has the potential to perform that catalytic act of reproducing itself?

RNA

What could help RNA be both an information storage unit and a self-replicating molecule?

it can act as a template for making copies of itself

Why is RNA thought to predate DNA in evolution?

the sugar in RNA is easier to make with the organic molecules that were present on primitive Earth

DNA is a better molecule for long-term storage of genetic information than RNA because

the deoxyribose sugar stabilizes DNA chains

What is true of hydrophilic molecules?

they mix well with water

What distinguishes the chemistry of life from other types of chemistry?

• its dominated by collections of polymers

• it takes place almost exclusively in water

Adenosine triphosphate (ATP) is a crucially important energy carrier in cells. True or false?

true

Saturated hydrocarbons are

• single carbon-carbon bonds

• are not flexible (straight)

Unsaturated hydrocarbons are

• double carbon-carbon bonds

• are flexible

Unsaturated and saturated hydrocarbons are

lipids

The term used to describe fatty acids that have both hydrophobic and hydrophilic components within the same molecule

amphipathic

When water is expelled, it is considered a

condensation reaction

When water is consumed, it is considered a

hydrolysis reaction

What chemical group is found in a nucleotide but not in a nucleoside?

phosphate

Nucleotides contain

a sugar, nitrogenous base, and a phosphate(s)

Nucleosides contain

a sugar and nitrogenous base

What is the covalent linkage between two adjacent amino acids in a protein called?

peptide bond

What chemical group is found on ALL amino acids?

carboxylic acid group

Amino acids are subunits of what macromolecule?

proteins

Why do phospholipids aggregate to form cell membranes?

because they are amphipathic

Lipids can include

• steroids

• triacylglycerol

• oils

• fatty acids

What do lipids not include?

amino acids

Which term describes a hydrocarbon tail of a fatty acid that has no double bonds between its carbon atoms?

saturated

What term best describes a fatty acid?

amphipathic

What type of reaction is the reverse of a condensation reaction?

hydrolysis

Sugars are linked together when a covalent bond forms between an -OH group on one molecule and an -OH group on another. When this bond forms, what molecule is released?

H2O

Most of the organic matter in a living organism consists of macromolecules, with a much smaller contribution from the small molecules that serve as potential subunits for macromolecules. True or false?

true

How are covalent bonds in the cell rapidly broken?

by enzyme catalysis that is specific between protein and substrate

Serine and glucose are considered to be

hydrophilic

Triacylglycerols and benzene are considered to be

hydrophobic

A phospholipid are considered to be

amphipathic

Glucose + glucose yield maltose + H2O is considered a

condensation reaction

ATP + H2O yield ADP + phosphate
PIP2 + H2O yield DAG + IP3
are considered to be

hydrolysis reactions

H2O2 + H2O2 yields 2 H2O + O2
CH3OH + HCl yields CH3Cl + H2O
are considered to be

neither condensation or hydrolysis reactions

Nucleotides are subunits of

nucleic acids

Amino acids are subunits of

proteins

Sugars (monosaccharides) are subunits of

polysaccharides/carbohydrates

Which type of bond makes it possible for a macromolecule to interact with great specificity with just one out of the many thousands of different molecules present inside a cell?

noncovalent bonds

How do protein, nucleic acid, and polysaccharide molecules polymerize (grow in length)?

by condensation reactions

Long polymers are made from single subunits in cells using a

condensation reaction, which releases water

What is the name used for a molecule in which two carbons of glycerol are attached to fatty acid chains, and the third carbon is attached to a phosphate group?

phospholipid

Which way do the fatty acid tails of a phospholipid face in a cell membrane?

both directions

Unsaturated fatty acids form a

fluid membrane

All amino acids have what chemical groups in common?

carboxyl group

Amino acids with side chains that contain -COOh groups, would be

acidic in the aqueous environment of a cell