BIO 351 EXAM 1 (CH 1,5,6)

The process by which cells take in substances

"Cell eating," where cells engulf large particles

"Cell drinking," where cells take in liquids

Specific uptake of molecules that bind to receptors on the cell surface, such as the entry of HIV into T cell

The process by which cells expel materials, involving vesicles that fuse with the cell membrane to release their contents

Provides structural support to the cell and is involved in intracellular transport and cell division

Commonly used for studies on DNA, RNA, and protein expression due to its simplicity and rapid reproduction cycle

A process where a gene is copied, allowing one copy to mutate without affecting the organism's essential functions. This can lead to the evolution of new functions, as seen with hemoglobin and myoglobin

Genes in different species that evolved from a common ancestor

Similar genes within the same species that arose from gene duplication

Used to determine the evolutionary relationships between organisms by comparing sequences. Constant and variable regions in this gene help identify relatedness

Involves sequencing the 16S rRNA gene from environmental samples to identify microbial communities

smooth strain of Streptococcus pneumoniae is virulent due to its capsule. When mice were injected with the smooth strain, they died

non-virulent and lacks a capsule. When mice were injected with the rough strain, they survived

An experiment showed that when the rough strain was infected alongside the smooth strain, some rough bacteria transformed into smooth ones, indicating a transfer of some factor from the smooth strain

Heating the smooth strain killed the bacteria, and when injected alone, the mice survived. However, mixing heat-killed smooth strain with live rough strain resulted in the death of the mice, suggesting that the transformation factor was still active

Through a series of tests using enzymes that break down carbohydrates, lipids, proteins, and nucleic acids, it was concluded that DNA is the molecule responsible for carrying genetic information. When DNA was degraded, the transformation did not occur, confirming that DNA is the genetic material

Hershey and Chase used bacteriophages to determine whether DNA or protein was the genetic material. They labeled the DNA with radioactive phosphorus and the protein with radioactive sulfur. After allowing the phages to infect bacteria, they found that only the radioactive phosphorus (DNA) entered the bacterial cells, confirming DNA as the genetic material

DNA is wrapped around histone proteins, forming nucleosomes. Approximately 147 nucleotides of DNA are wrapped around each nucleosome, contributing to the first level of DNA compaction

The second level of compaction involves the formation of a 30 nanometer fiber, and further compaction occurs during metaphase when chromosomes are fully condensed

Enzymes such as ATP-dependent chromatin remodeling complexes use ATP to reposition DNA around nucleosomes, allowing access for transcription and replication

The tails of histones can be modified (e.g., methylation and acetylation), which affects the accessibility of DNA. Methylation typically leads to tighter compaction, while acetylation loosens the grip of DNA on histones, facilitating access for enzymes

tightly packed and transcriptionally inactive

loosely packed and active in transcription

a technique used to amplify specific segments of DNA. It allows researchers to create millions of copies of a particular DNA sequence from a small initial sample

The specific DNA segment you want to amplify.

Short sequences of nucleotides that are complementary to the target DNA region. Two primers are needed for each strand of the DNA.

An enzyme that synthesizes new DNA strands. The commonly used polymerase is Taq polymerase, which is heat-stable and allows the reaction to proceed at high temperatures.

The building blocks of DNA, specifically deoxyribonucleotides.

Provides the optimal environment for the enzyme to function.

The reaction mixture is heated to approximately 95°C to separate the double-stranded DNA into single strands by breaking the hydrogen bonds.

The temperature is lowered (typically to 60-65°C) to allow the primers to bind (anneal) to their complementary sequences on the single-stranded DNA.

The temperature is raised to around 72°C, the optimal temperature for Taq polymerase to synthesize new DNA strands by adding nucleotides complementary to the template strand.

The process by which DNA makes a copy of itself, essential for cell division and inheritance.

A fundamental mechanism that underlies both DNA replication and repair, where adenine (A) pairs with thymine (T) and guanine (G) pairs with cytosine (C)

DNA replication begins at specific locations called replication origins
In eukaryotes, replication starts at multiple sites, each used at different frequencies

Two replication forks form at each replication origin
The replication fork is asymmetrical, with one strand synthesized continuously (leading strand) and the other synthesized discontinuously (lagging strand)

DNA Polymerase synthesizes new DNA strands using a parent strand as a template
It is self-correcting, proofreading its work to ensure high fidelity during DNA synthesis

Short lengths of RNA act as primers for DNA synthesis, especially on the lagging strand
In eukaryotes, RNA primers are synthesized at intervals of about 200 nucleotides

Proteins at the replication fork cooperate to form a replication machine, including helicases that unwind the DNA double helix
Single-strand binding proteins stabilize the unwound DNA

After RNA primers are removed by nucleases, DNA polymerase replaces them with DNA, and DNA ligase seals the gaps between Okazaki fragments on the lagging strand

Catalyzes nucleotide addition and proofreads DNA

Unwinds the DNA double helix

Prevents reformation of base pairs

Relieves tension in the DNA strand

Keeps DNA polymerase attached to the template

Locks the sliding clamp onto DNA

Synthesizes RNA primers

Joins Okazaki fragments

Involves deletion of DNA sequences at the repair site

Repairs double-strand breaks accurately using undamaged DNA as a template, preserving nucleotide sequences