Heredity and DNA Flashcards
Define
Heredity
Passing of phenotypes from one generation to the next
Define
Phenotype
Physical, heritable traits
What questions needed to be answered to understand inheritance?
Is there a pattern to how traits are inherited?
What is physically being inherited?
How does the inherited material lead to an individual’s phenotype?
Describe the work of
Gregor Mendel
Scientist that used pea plants to test how traits were inherited;
Found that phenotypes were passed in discrete units
Define
Genes
Discrete units of inheritance;
Stretches of DNA that code for specific proteins
Describe the work of
Watson & Crick
Scientists that studied DNA and discovered its structure and how it replicated
Define
Chromosome
Physical structures made of DNA and protein in the nucleus of cells
Copied and passed from parent cell to each new cell during cell division
Define the
Central Dogma
A description of the flow of genetic information, from DNA to RNA to protein
Define
Genome
The “instruction book” of genes that makes up an organism
Define
Nucleotide
Monomer of nucleotides
List the
Parts of a nucleotide
Phosphate group
Five-carbon sugar (“pentose”)
Nitrogenous base
Define
Deoxyribose
The pentose / five-carbon sugar used in DNA
What are the nitrogenous bases found in DNA?
Adenine (A)
Thymine (T)
Cytosine (C)
Guanine (G)
How do nucleotides join together to form a strand of nucleic acid?
Covalent bonds form between the phosphate of one nucleotide and the five-carbon sugar (pentose) of the next nucleotide
Nitrogenous bases stick off to the side of the strand
Define the
Double helix
A common description of the shape of DNA, since it is made of two strands and twists together like a ladder
Describe the
“Backbone” of DNA
Alternating sugar and phosphates that make up the sides of the DNA ladder
Describe the
“Rungs” of DNA
Rungs = the part of a ladder that go across (that you step on)
Pairs of nitrogenous bases, which are joined together with hydrogen bonds
Define
Antiparallel
The two strands of DNA are oriented in opposite directions
Define
Complementary Base Pairing
Nitrogenous bases always bind together in a specific way, due to the size and number of hydrogen bonds on each nitrogenous base
Complementary = two things that “complete” each other
State
Base Pairing Rules in DNA
Adenine and Thymine always pair
Cytosine and Guanine always pair
Describe the relationship between
DNA, Genes, Nucleotides, and Chromosomes
Nucleotides are the individual monomers that string together to make DNA;
A DNA molecule is millions or billions of nucleotides long;
A segment of DNA that codes for a specific protein makes up one gene; and
Each chromosome consists of a DNA molecule (encompassing dozens, hundreds, or thousands of genes) along with proteins that help it coil
Define
Chromatin
DNA that is not tightly coiled into chromosomes, which is visible during most of the cell’s life cycle
Describe the
Human Genome
About 20,000 genes, organized into two pairs of 23 chromosomes
Define
Diploid
Organisms and/or cells that contain two sets of chromosomes
Define
Haploid
Organisms and/or cells that contain one set of chromosomes
Define
Autosomes
Chromosomes that are found in pairs in diploid organisms;
In humans, chromosomes 1 - 22
Define
Sex chromosomes
Chromosomes that are not autosomes, and often determine the sex of individuals;
In humans, X and Y
Define
Genetic Females
Humans with two X chromosomes
Define
Genetic Males
Humans with an X and Y chromosome
Define
Karyotype
A picture of the chromosomes of an organism, arranged from largest to smallest
What is being shown in the purple box?
A nucleotide
What is being shown in the purple box?
A base pair
Two complementary nucleotides that are joined together
What kind of bond is being shown?
Covalent
Form between nucleotides on one strand of DNA
What kind of bond would form where the purple arrow indicates?
Hydrogen bond
