Biology Chapter: DNA and Chromosomes

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson
Download our mobile app to listen on the go
Get App

Questions and Answers

Carbohydrates and Lipids can self-replicate.

False (B)

What is the main effect of histone acetylation on chromatin packing?

Loosens packing

Which of the following statements is TRUE about histone methylation?

  • It always leads to tighter chromatin packing.
  • It has no effect on chromatin packing.
  • It can have both loosening and tightening effects, depending on the specific methylation site. (correct)
  • It always leads to looser chromatin packing.

The enzyme that adds acetyl groups to histone proteins is called a ______.

<p>histone acetyltransferase (HAT)</p> Signup and view all the answers

Match the following molecules with their primary location within a cell:

<p>Carbohydrates = Distributed throughout the cell Lipids = Distributed throughout the cell Proteins = Distributed throughout the cell Nucleic Acids = Concentrated in the nucleus</p> Signup and view all the answers

Which of the following DNA sequences is complementary to 5'-TAGAC-3'?

<p>5'-GTCTA-3' (C)</p> Signup and view all the answers

DNA in eukaryotic cells is organized into circular chromosomes and located in the nucleus.

<p>False (B)</p> Signup and view all the answers

Which of the following is NOT a characteristic of DNA organization in eukaryotes?

<p>dsDNA is organized into circular chromosomes and located in the nucleus. (E)</p> Signup and view all the answers

Condensins decondense chromosomes after mitosis.

<p>True (A)</p> Signup and view all the answers

Nucleosomes coil and stack into ______ chromatin fibers.

<p>30nm</p> Signup and view all the answers

In a diploid organism with a haploid number (n) of 4 chromosomes, how many chromosomes are present in somatic cells? How many chromosomes are present in mature gamete cells?

<p>Somatic cells: 8 chromosomes. Mature gamete cells: 4 chromosomes.</p> Signup and view all the answers

Match the following nitrogenous bases with their correct category.

<p>Adenine = Purine Guanine = Purine Cytosine = Pyrimidine Thymine = Pyrimidine Uracil = Pyrimidine</p> Signup and view all the answers

List four classes of macromolecules that were once considered possible carriers of genetic information.

<p>Carbohydrates, Lipids, Proteins, and Nucleic Acids</p> Signup and view all the answers

Which of the following is the most complete and correct definition of a gene?

<p>Specific segment of DNA in a discrete region of a chromosome that codes for a functional product (A)</p> Signup and view all the answers

Mendel's law of segregation explains that the alleles for one gene (Aa) and the alleles for another gene (Bb) will be found in equal proportions in the offspring.

<p>False (B)</p> Signup and view all the answers

The temperature that causes hydrogen bonds between bases to break is referred to as the ______.

<p>Tm</p> Signup and view all the answers

What is the role of topoisomerases in DNA replication?

<p>Topoisomerases are enzymes that help to prevent the overwinding of DNA during replication by cutting and rejoining DNA strands. This allows the DNA strands to be separated and replicated without tangling.</p> Signup and view all the answers

Match the following terms with their definitions:

<p>Tm = The temperature at which 50% of the DNA molecules are denatured Topoisomerase = An enzyme that relieves torsional stress in DNA Gene = A specific segment of DNA that codes for a functional product Law of segregation = Alleles for a trait separate during gamete formation Law of independent assortment = Alleles for different traits segregate independently during gamete formation</p> Signup and view all the answers

Which of the following statements is true about Tm?

<p>Tm is higher when the GC content of the sequence is higher. (C), Tm refers to the temperature that causes hydrogen bonds between bases to break. (D)</p> Signup and view all the answers

Topoisomerases are only found in bacteria, not eukaryotes.

<p>False (B)</p> Signup and view all the answers

According to Mendel's law of ______, if the parent genotype is Aa, the probability of getting allele A or allele a in a gamete is equally likely.

<p>segregation</p> Signup and view all the answers

Signup and view all the answers

Flashcards

Gene definition

A specific segment of DNA in a discrete region of a chromosome that codes for a functional product.

Mendel's Law of Independent Assortment

Alleles for one gene segregate independently of alleles for another gene during gamete formation.

Mendel's Law of Segregation

Each individual has two alleles for each gene, which segregate into gametes with equal probability.

Tm (melting temperature)

The temperature at which hydrogen bonds between DNA bases break, causing strands to separate.

Signup and view all the flashcards

Topoisomerases

Proteins that modify the supercoiling of DNA, enabling additional twists to be added or removed.

Signup and view all the flashcards

Role of DNA in proteins

DNA codes for proteins which determine organism traits and functions.

Signup and view all the flashcards

Gamete formation

The process where alleles segregate to ensure genetic variation in offspring.

Signup and view all the flashcards

Hydrogen bonds in DNA

Weak bonds between nitrogenous bases that hold the two strands of DNA together.

Signup and view all the flashcards

Carbohydrates

Organic compounds made of carbon, hydrogen, and oxygen, typically used for energy and structural support in cells.

Signup and view all the flashcards

Proteins

Large biomolecules composed of amino acids, essential for the structure, function, and regulation of the body's tissues and organs.

Signup and view all the flashcards

Nucleic Acids

Biomacromolecules such as DNA and RNA that carry genetic information vital for heredity and protein synthesis.

Signup and view all the flashcards

Role of Acetylation in Histone Modification

A process where acetyl groups are added to histones, neutralizing their positive charge and loosening chromatin packing.

Signup and view all the flashcards

Role of Methylation in Histone Modification

A process where methyl groups are added to histones, leading to no change in histone charge but can either increase or tighten chromatin packing depending on context.

Signup and view all the flashcards

Complementary DNA Sequence

A DNA sequence that pairs with a given sequence, following base pairing rules.

Signup and view all the flashcards

DNA Organization in Eukaryotes

Eukaryotic DNA is organized into linear chromosomes in the nucleus.

Signup and view all the flashcards

Nucleosomes

Units of DNA wrapped around histone proteins, aiding in DNA compaction.

Signup and view all the flashcards

Chromatin Packaging

The process by which DNA is condensed and organized in chromosomes.

Signup and view all the flashcards

Diploid Chromosome Count

In diploid organisms, the number of chromosomes in somatic cells is twice the haploid number.

Signup and view all the flashcards

Pyrimidines

Single-ring nitrogenous bases in DNA: Cytosine, Thymine (and Uracil in RNA).

Signup and view all the flashcards

Purines

Double-ring nitrogenous bases in DNA: Adenine and Guanine.

Signup and view all the flashcards

Macromolecules in Cells

Four classes of biomolecules: Carbohydrates, Lipids, Proteins, and Nucleic Acids.

Signup and view all the flashcards

Study Notes

DNA, Chromosomes, Structure

  • Gene Definition: A specific segment of DNA within a chromosome that codes for a functional product, usually a protein.
  • Mendel's Law of Independent Assortment: The probability of inheriting one allele from a parent is equally likely for any given allele.
  • Mendel's Law of Segregation: In gamete formation, the alleles for a given gene separate, and each gamete receives only one allele.
  • DNA Structure: Double helix; nitrogenous bases (adenine, guanine, cytosine, and thymine) paired together.
  • Topoisomerases: Enzymes that modify DNA structure by adding or removing twists, facilitating DNA replication and compaction.
  • Denaturation Temperature: The temperature at which DNA's phosphodiester or hydrogen bonds break. The higher the GC content, the higher the denaturation temperature.
  • Eukaryotic DNA Organization: DNA is associated with proteins (histones) to form a complex called chromatin, highly organized into specific regions within the nucleus.
  • Eukaryotic Chromatin Structure: DNA segments are organized into nucleosome structures, coiled and stacked into 30nm chromatin fibers.
  • Chromosome Packaging: Chromosomes condense extensively before cell division.
  • Complementary DNA Sequence: The complementary sequence to 5'-TAGAC-3' is 5'-ATCTG-3'.
  • DNA bases: Cytosine, adenine, guanine, thymine, uracil.
  • Pyrimidines: Single-ring structures (Cytosine, thymine, uracil)
  • Purines: Double-ring structures (Adenine, guanine)
  • Somatic Cells: Diploid cells with 8 chromosomes in this example.
  • Mature Gamete Cells: Haploid cells with 4 chromosomes in this example.

Histone Modification

  • Acetylation: Neutralizes positive charge on histones, allowing chromatin to loosen.
  • Methylation: Histone modification without charge alteration, causing chromatin compaction sometimes.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Weekly Homework - DNA, Chromosomes, Structure - PDF

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser