DNA Flashcards
Adenine can form only with
ThyminE
Hydrogen bonds can form only between
Certain base pairs
Guanine can form only with
Cytosine
What is base pairing
When hydrogen bonds can form only between certain base pairs
Why A=T And G=C
For every adenine in a double-stranded DNA molecule there had to be exactly one find me molecule; for each site is the molecule there was one wanting molecule
Prokaryotic cells lack
Nuclei and many of the organelles found in eukaryotes
What is the location of DNA in prokaryotic cells
Cytoplasm
What is the cells chromosome
Most prokaryotes have a single cellular DNA molecule that contains nearly all of the cells genetic information and this large DNA molecule is referred to as the cells chromosome
Eukaryotic DNA is generally located in the
Cell nucleus in the form of a number of chromosomes
Is the sentence true or false? Most prokaryotes contain a single, circular DNA molecule
True
Do all organisms have the same number of chromosomes
No the number of chromosomes very widely from one species to the next
is the following sentence true or false? The E. coli chromosome is longer than the diameter of an individual E. coli bacteria
True
What are chromatin
Eukaryotic chromosomes contain both DNA and protein, tightly packed together to form a substance called chromatin
What do chromatin consist of
DNA that is tightly coiled around proteins called histones
What do the DNA and histone molecules form
A bed like structure called a nucleosome. Nucleosomes pack with one another to form a thick fiber, which is shortened by a system of loops and coils
Why are individual chromosomes visible only during mitosis
During most of the cell cycle these fibers are disbursed into the nucleus so that individual chromosomes are not visible. During mitosis however the fibers of each individual chromosomes are drawn together forming the tightly packed chromosomes you can see through a light microscope in dividing cells.
Are changes in chromatin structure and histone DNA-binding associated with changes in gene activity
Yes
What are nucleosome’s and their function
They seem to be able to fold enormous lengths of DNA into the tiny space available in the cell nucleus. This is such an important function at the histone proteins them selves have changed very little during evolution probably because mistakes in DNA folding could harm the cells ability to reproduce
Each strand of the DNA double helix has
All the information needed to reconstruct the other half by the mechanism of base pairing
The DNA molecule______ or unzips into two strands
Separates
Each strand serves as a_____ or model to produce new strands
Template
Two new_____ strands are produced, following the rules of _______
Complementary
Base pairing
Is the following sentence true or false? Eukaryotic chromosomes DNA replication begins at a single point in the chromosomes and proceeds into directions
False
The site where DNA replication and separation occur are called
Replication forks
What occurs when a molecule of DNA is unzipped
Hydrogen bonds between the base pairs are broken and the two strands of the molecule unwind
What is the complementary strand of bases for a strand with the bases TACGTT
ATGCAA
Is the following sentence true or false? Each DNA molecule resulting from replication has one original strand and one new strand
True
List two major roles of DNA polymerized in the process of DNA replication
Joins individual nucleotides to produce a DNA molecule
Proofreads each new DNA strand helping to maximize the odds that each molecule is a perfect copy of the original DNA
What is helicase
An enzyme that unwinds the double helix by technically slicing apart the loose hydrogen bonds
Is the top strands of the double helix called
The leading strand
What is the bottom strand of the double helix called
The lagging strand
His DNA polymerase
An enzyme that adds matching nucleotides to the main stem all the way down the molecule
DNA polymerase can only copy strands in the
5’—3’ direction
What is DNA licase
Little fragments get joined by DNA ligase- seals the nicks between Okazaki fragments, SSPBS, and fall away DNA recoils
What are the 3 things that make up nucleic acids
Carbon sugar molecule
Phosphate group
1 of 4 nitrogen bases
What is deoxyribose
The sugar molecule that makes up part of DNA
