Cell Biology: DNA Location

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Questions and Answers

Match the following nitrogenous bases with their hydrogen bond partners:

Adenine = Thymine or Uracil Cytosine = Guanine Guanine = Thymine or Uracil Thymine = Cytosine

Match the following components with their functions in the DNA molecule:

Sugar molecule = Forms the backbone of DNA Phosphate molecule = Provides energy for DNA synthesis Nitrogenous base = Provides structural support to DNA Histone proteins = Influences gene expression

Match the following terms with their definitions:

Chromatin = The network of chromosomes in the nucleus Chromosomes = The complex of DNA, RNA, and histone proteins Extranuclear DNA = DNA found in the mitochondria and chloroplasts Nucleotides = The building blocks of RNA

Match the following nitrogenous bases with their classification:

Adenine = Purine Uracil = Pyrimidine Thymine = Purine Cytosine = Pyrimidine Signup and view all the answers

Match the following structures with their locations in a cell:

Mitochondria = Found in the nucleus Chloroplasts = Found in plant cells Nucleus = Found in the cytoplasm Chromatin = Found in the cytoplasm Signup and view all the answers

Match the following terms with their descriptions:

Deoxyribose = A type of sugar molecule Phosphate molecule = A type of nitrogenous base Histone proteins = A type of sugar molecule Cytosine = A type of phosphate molecule Signup and view all the answers

Match the following characteristics with the correct type of nitrogenous base:

Made up of one ring of atoms = Pyrimidine Made up of two fused rings of atoms = Purine Found in RNA = Uracil Smaller in size = Purine Signup and view all the answers

Match the following terms with their functions in the DNA double helix:

Sugar/phosphate links = Forms the rungs of the ladder Hydrogen bonds = Forms the backbone of DNA Base pairs = Provides structural support to DNA Nitrogenous bases = Holds the DNA molecule together Signup and view all the answers

Match the following statements with the correct function of DNA:

Carries hereditary information = Genes Provides a blueprint for protein synthesis = Blueprint Can replicate itself = Replication Determines the genetic code = Genetic code Signup and view all the answers

Match the following terms with their characteristics:

Adenine = Has three hydrogen bonds Thymine = Has two hydrogen bonds Guanine = Has two hydrogen bonds Cytosine = Has three hydrogen bonds Signup and view all the answers

Match the following terms with their definitions:

Exons = Protein-coding regions Introns = Non-coding regions Signup and view all the answers

Match the following statements with the correct characteristic of DNA:

Less than 2% of human DNA codes for proteins = Non-coding DNA More than 2% of human DNA codes for proteins = Protein-coding DNA Found only in complex organisms = Non-coding DNA Found only in less complex organisms = Protein-coding DNA Signup and view all the answers

Match the following components with their roles in the genetic code:

Sugar molecule = Instructs cells on protein synthesis Phosphate molecule = Provides energy for DNA synthesis Nitrogenous bases = Instructs cells on protein synthesis Histone proteins = Influences gene expression Signup and view all the answers

Match the following nitrogenous bases with their occurrence in DNA:

Uracil = Only in RNA Thymine = Only in DNA Adenine = Found in both DNA and RNA Cytosine = Found in both DNA and RNA Signup and view all the answers

Match the following statements with the correct function of DNA replication:

Ensures genetic code is passed on to daughter cells = Replication Provides a blueprint for protein synthesis = Blueprint Carries hereditary information = Genes Determines the sequence of nucleotides = Genetic code Signup and view all the answers

Match the following terms with their definitions:

Genetic code = The sequence of nucleotides that determines the genetic information Genes = The blueprint for protein synthesis Protein synthesis = The process of creating proteins from DNA Replication = The process of creating a copy of DNA Signup and view all the answers

Study Notes

Where is DNA Found?

DNA is mainly found in the nucleus of a cell, forming part of the chromatin network.
Small amounts of DNA are also found outside the nucleus in mitochondria and chloroplasts, known as extranuclear DNA.

Structure of DNA

DNA is a long, twisted ladder-like molecule that forms a stable, 3-dimensional double helix.
The DNA molecule is made up of nucleotides, which are building blocks consisting of a sugar molecule, a phosphate molecule, and a nitrogenous base.

Nucleotides

There are four types of nitrogenous bases: adenine (A), thymine (T), guanine (G), and cytosine (C).
These four bases are the foundation of the genetic code, instructing cells on how to synthesize enzymes and other proteins.

Double Helix Structure

The outer two strands of the ladder are formed by a chain of alternating sugar and phosphate links.
The rungs of the ladder are formed from pairs of bases linked by weak hydrogen bonds.
The base pairs are attached to the sugar molecules.

Base Pairing

Adenine (A) pairs with thymine (T) or uracil (U) using two hydrogen bonds.
Cytosine (C) pairs with guanine (G) using three hydrogen bonds.

Classification of Nitrogenous Bases

There are two groups of nitrogenous bases: purines and pyrimidines.
Purines consist of two fused rings of nitrogen, carbon, and hydrogen atoms (e.g. guanine and adenine).
Pyrimidines consist of one ring of similar atoms and are smaller than purines (e.g. cytosine and uracil).

Universality of DNA

The four nucleotides are the same in all animals and plants.

Genetic Code

The sequence of nucleotides determines the genetic code of an organism.
The sequence of nucleotides in certain sections of DNA in a human is different from the same sections in every other human being (except in identical twins).

Role of DNA

DNA molecules carry hereditary information in the form of genes.
DNA provides a blueprint for an organism's growth and development by coding for protein synthesis.
DNA can replicate, making a copy of itself to pass on genetic information to each daughter cell during cell division.

Non-Coding DNA

Less than 2% of human DNA codes for proteins; the rest consists of non-coding DNA.
Non-coding regions are interrupted by protein-coding regions called exons.
Complex organisms contain more non-coding DNA than less complex organisms.