Biology unit 2 test
The main function of a mRNA molecule is to?
Carry DNA's genetic message for translation
After DNA replication, a eukaryotic chromosome_______
Consists of 2 sister chromatids, has characteristic X shape, is constricted at the centromere
DNA replication requires ____
DNA polymerase, nucleotides, and primers
Variation in ___ is the basis of variation in traits.
DNA sequence
The phase 5 to 3 refers to the ____
Directionality of DNA synthesis
Most codons specify a(n) _____.
amino acid
Enzymes contained in _____ break down worn-out organelles, bacteria, and other particles.
lysosomes
Anticodons pair with
mRNA codons
Solutes tend to diffuse from a region where they are __ concentrated to another where they are ___ concentrated
more, less
What controls the passage of molecules into and out of the nucleus?
nuclear pores, which consist of membrane proteins
Where does transcription occur?
nucleus
Every cell is descended from another cell. This idea is part of ____.
cell theory
All mutations _____
change in DNA sequence
The surface-to-volume ratio
constrains cell size and is part of cell theory
Where does translation occur?
cytoplasm
Despite the diversity of cell type and function, all cells have these three things in common:
cytoplasm, DNA, and a plasma membrane
All antioxidants ______
prevent other molecules from being oxidized
A binding site for RNA polymerase is called a _____.
promoter
_____ are always changed by participating in a reaction
reactants
An RNA molecule is typically ___; A DNA molecule is typically ___
single stranded, double stranded
Up to ___ amino acids can be encoded by an mRNA that consists of 45 nucleotides plus a stop codon
15
What are the base pairing rules for DNA?
A=T and C=G
Energy that drives DNA synthesis comes from _______
ATP and DNA nucleotides
___ connect the cytoplasm of plant cells
Adhesion protein
A metabolic pathway may _____
Build or break down molecules, include electron transfer chain, generate heat
____ can change from one form to another
Energy
Only _____ cells have mitochondria
Eukaryotic
Energy that drives translation is provided mainly by_____
GTP
_______ is not a nucleotide base in DNA?
Glutamine
One species' DNA differs from others in its
Nucleotides, DNA sequence, sugar-phosphate backbone
Cell membranes consist mainly of ____ and ____
Phospholipids; protein
Correct order according to pathway of secreted proteins...
Plasma membrane, endoplasmic reticulum, Golgi bodies, post-Golgi vesicles
Most of a membrane's diverse functions are carried out by ____.
Proteins
Energy that drives transcription is provided mainly by ___
RNA nucleotides
A chromosome contains many different gene regions that are transcribed into different
RNAs
_____ is an example of reproductive cloning
SCNT and artificial embryo splitting
_____ is life's primary source of energy
Sunlight
Human body cells are diploid, which means _____.
They have two sets of chromosomes
A transport protein requires ATP to pump sodium ions across a membrane, this is a case of _____
active transport
If we liken a chemical reaction to an energy hill, then activation energy is like
a bump at the top of the hill
Entropy ____
a measure of disorder, always increases
The main function of the endomembrane system is ____.
building and modifying proteins and lipids
Immerse a human blood cell in a hypotonic solution, and water ______
diffuses into the cell
If we liken a chemical reaction to an energy hill, then a(n) _____ reaction is an uphill run
endergonic
Vesicles form during ______
endocytosis and phagocytosis
Unlike eukaryotic cells, prokaryotic cells
have no nucleus
Eukaryotic chromosomes, DNA wraps around?
histone proteins
In a lipid bilayer, _______ of all the lipid molecules are sandwiched between all the _______.
hydrophobic tails and hydrophilic heads
_____ are removed from new mRNAs
introns
______ cannot easily diffuse across a lipid bilayer
ions
Chromosome number ______
is an identifiable feature of a species
The main function of DNA molecule is to _____
store heritable information
Name one environmental factor that typically influences enzyme function.
temperature, pH, salt, pressure
When DNA replication begins,
the two DNA strands unwind from each other
RNAs form by _____; proteins form by _____.
transcription and translation
