Question 1

The process of ______ results in a zygote being created with 23 pairs of chromosomes.

Accepted Answer

Fertilization is the process where an egg and sperm cell merge, resulting in the formation of a zygote with 23 pairs of chromosomes, combining genetic material from both parents.

Question 2

A fertilized egg, which eventually develops into an organism, is initially called a(n) ______.

Accepted Answer

A fertilized egg is initially called a zygote, which is the earliest developmental stage of the embryo before it begins dividing and growing into a more complex organism.

Question 3

Kathryn recently took a pregnancy test and discovered that she was pregnant. When she went to her doctor for an examination, she discovered that she had been pregnant for 5 weeks. What term do scientists used to refer to the fertilized egg that is developing in Kathryn's uterus?

Accepted Answer

During the first 8 weeks following fertilization, the developing organism is called an embryo. Since Kathryn is 5 weeks pregnant, the correct term is embryo.

Question 4

Most pregnant women undergo regular medical evaluations of their pregnancies beginning at 8 weeks after fertilization. At this point in development, the fertilized egg is referred to by scientists as a(n) ______.

Accepted Answer

The answer of Most pregnant women undergo regular medical evaluations...

Question 5

Which scientists are known for reporting that DNA is structured in a double helix?

Accepted Answer

James Watson and Francis Crick are credited with the discovery of the double helix structure of DNA in 1953, which is a fundamental concept in the field of genetics.

Question 6

What does the "double helix" refer to?

Accepted Answer

The "double helix" refers to the twisted ladder-like structure of DNA, where two strands of nucleotides wind around each other to form a double spiral, resembling a twisted ladder. This structure was first described by James Watson and Francis Crick in 1953.

Question 7

Which of the following is a nucleotide that makes up DNA?

Accepted Answer

Guanine is one of the four nucleotides that make up DNA, alongside adenine, cytosine, and thymine. Uracil is found in RNA, not DNA, and GABA and acetylcholine are neurotransmitters, not components of DNA.

Question 8

Adenine, thymine, guanine, and cytosine are nucleotides that make up ______.

Accepted Answer

Adenine, thymine, guanine, and cytosine are nucleotides that make up DNA. In RNA, thymine is replaced by uracil.

Question 9

The code for our genetic information is carried in which of the following?

Accepted Answer

The order of nucleotides on our DNA strands carries the genetic information, acting as a code that determines genetic traits and the synthesis of proteins.

Question 10

Which of the following is a true statement about enzymes in the body?

Accepted Answer

Enzymes are proteins that catalyze biochemical reactions, and like all proteins, they are coded for by genes in the DNA. This allows for the synthesis of specific enzymes as required by the body's metabolic needs.

Question 11

Chemical reactions in the body can be modified by ______, which are coded for by genes.

Accepted Answer

Enzymes are biological molecules that significantly speed up the rate of virtually all of the chemical reactions that take place within cells. They are vital for life and serve as catalysts for specific and essential chemical reactions in the body's cells. Enzymes are indeed coded for by genes, with each enzyme being the product of a specific gene or set of genes.

Question 12

Which of the following is a true statement about genes?

Accepted Answer

The Y chromosome is significantly smaller than the X chromosome and contains fewer genes. This difference is a key factor in sex determination and contributes to the genetic differences between males and females.

Question 13

Type AB blood is an example of ______.

Accepted Answer

Type AB blood is an example of codominance, where both A and B alleles are expressed equally, leading to a blend of both characteristics without one being dominant over the other.

Question 14

Keysha's mother is homozygous for a dominant allele for unattached earlobes and her father is homozygous for a recessive allele for attached earlobes. What is true about Keysha's earlobes?

Accepted Answer

Keysha's mother's homozygous dominant genotype for unattached earlobes means she can only pass on the dominant allele for unattached earlobes. Her father's homozygous recessive genotype for attached earlobes means he can only pass on the recessive allele for attached earlobes. Therefore, Keysha must inherit one dominant allele for unattached earlobes from her mother and one recessive allele for attached earlobes from her father, making her phenotype for unattached earlobes.

Question 15

Keysha's mother is homozygous for a dominant allele for unattached earlobes and her father is heterozygous for a recessive allele for attached earlobes. Keysha has two siblings. What of the following is a true statement about Keysha and her siblings?

Accepted Answer

Since Keysha's mother has a homozygous dominant allele for unattached earlobes, all her children will inherit one dominant allele for unattached earlobes. Regardless of whether they inherit the dominant or recessive allele from their father, the presence of at least one dominant allele will result in the phenotype for unattached earlobes in all the children.

Question 16

Why are males more likely than females to have a deficiency in red-green color vision?

Accepted Answer

Males are more likely to have a deficiency in red-green color vision because the genes responsible for this condition are located on the X chromosome. Males have only one X chromosome (XY), while females have two (XX). If a male inherits an X chromosome with the mutation, he will express the condition, as there is no corresponding gene on the Y chromosome to counteract it. Females, on the other hand, would need to inherit the mutation on both of their X chromosomes to express the condition, making it less common among females.

Question 17

Neither of Sean's parents has a red-green color deficiency, but Sean does. Why is this possible?

Accepted Answer

Red-green color deficiency is X-linked recessive. Sean's mother can be a carrier (heterozygous) without expressing the trait, passing the recessive allele to Sean.

Question 18

How do modern psychologists approach the nature-versus-nurture question?

Accepted Answer

Modern psychologists generally agree that both nature (heredity) and nurture (environment) play significant roles in shaping behavior, rather than one being overwhelmingly more important than the other. This perspective acknowledges the complexity of human development and the interplay between genetic and environmental factors.

Question 19

What was the purpose of the Human Genome Project?

Accepted Answer

The Human Genome Project aimed to identify all the genes in human DNA, encompassing both their sequencing and mapping.

Question 20

When did the Human Genome Project take place?

Accepted Answer

The Human Genome Project officially began in 1990 and was completed in 2003, making the 1990s the decade when it took place.

Quiz 1: What Is Behavioral Neuroscience