Chapter 14: The Human Genome Flashcards

Questions and Answers

Biologists can analyze human chromosomes by looking at a __________.

karyotype

A karyotype is a picture of the chromosomes from a cell arranged in __________ pairs.

homologous

Humans have ____ chromosomes.

Two of these chromosomes, X and Y, are the ______ chromosomes.

sex Signup and view all the answers

Females have how many X chromosomes?

two Signup and view all the answers

Males have how many Y chromosomes?

one Signup and view all the answers

The other 44 chromosomes are called ______.

autosomes Signup and view all the answers

Human genes are inherited according to the same principles described by whom?

Mendel Signup and view all the answers

To study the inheritance of human traits, biologists use a __________.

pedigree chart Signup and view all the answers

A pedigree shows the relationships within a ______.

family Signup and view all the answers

The inheritance of a certain ______ in a family can be traced using a pedigree.

trait Signup and view all the answers

From this, biologists can infer the ______ of family members.

genotype Signup and view all the answers

It is difficult to associate an observed human trait with a ______.

specific gene Signup and view all the answers

Many human traits are _______, meaning that they are controlled by many genes.

polygenic Signup and view all the answers

The ______ also influences many traits.

environment Signup and view all the answers

Some of the first human genes to be identified were those that control __________.

blood type Signup and view all the answers

Red blood cells can carry two different antigens, called and .

A, B Signup and view all the answers

_________ are molecules that can be recognized by the immune system.

Antigens Signup and view all the answers

The presence or absence of the A and B antigens produces 4 possible blood types: __, _, , and .

A, B, AB, O Signup and view all the answers

The ABO blood types are determined by a single gene with ______.

three alleles Signup and view all the answers

In addition to the ABO antigens, there is another antigen on red blood cells called the ____________.

Rh antigen Signup and view all the answers

People without it are __________.

Rh negative Signup and view all the answers

People who have the Rh antigen are _________.

Rh positive Signup and view all the answers

A single with two ____ determines the Rh blood group.

gene, alleles Signup and view all the answers

There are several human genetic disorders, including _________, _, and _______________.

phenylketonuria, Huntington's disease, sickle cell disease Signup and view all the answers

PKU is caused by a __________________.

recessive allele Signup and view all the answers

It is expressed only in individuals who have __________ a recessive allele from each parent.

inherited Signup and view all the answers

Huntington's disease is caused by a ___________.

dominant allele Signup and view all the answers

It is _________ in any person who has that allele.

expressed Signup and view all the answers

Sickle cell disease is caused by a ____________.

codominant allele Signup and view all the answers

Scientists are beginning to understand which changes in the ______________ cause certain genetic disorders.

DNA sequence Signup and view all the answers

Cystic fibrosis is caused by what?

deletion of three bases Signup and view all the answers

This deletion ___________ the protein, which causes the symptoms of this disorder.

inactivates Signup and view all the answers

Only one ___________ is changed in the allele that causes sickle cell disease.

DNA base Signup and view all the answers

This base change produces a blood protein that is less ______ than normal.

soluble Signup and view all the answers

The two smallest human chromosomes, ______ and were the first chromosomes to have their DNA sequences identified.

chromosomes 21, 22 Signup and view all the answers

Both have many genes important for _________.

health Signup and view all the answers

Both have regions of DNA that do not ______ for proteins.

code Signup and view all the answers

Genes located on the X and Y chromosomes, the __, are said to be _.

sex chromosomes, sex-linked Signup and view all the answers

They are inherited in a different pattern than genes located on __________.

autosomes Signup and view all the answers

For example, all alleles linked to the X chromosome, including those responsible for , , and ___ are expressed in males even if they are recessive alleles.

color blindness, hemophilia, Duchenne muscular dystrophy Signup and view all the answers

However, in order for these recessive alleles to be expressed in _________, there must be two copies of them.

females Signup and view all the answers

Females have two __________.

X chromosomes Signup and view all the answers

________ have only one X chromosome.

Males Signup and view all the answers

To account for this difference, one X chromosome in females is randomly __________.

turned off Signup and view all the answers

The turned-off chromosome forms a dense region in the nucleus known as __________.

barr body Signup and view all the answers

Barr bodies are not found in whom?

males Signup and view all the answers

The most common error during meiosis is __________.

nondisjunction Signup and view all the answers

_____________ is the failure of the chromosomes to separate properly during meiosis.

Nondisjunction Signup and view all the answers

It causes abnormal numbers of chromosomes to find their way into __________.

gametes Signup and view all the answers

This may result in a disorder of __________.

chromosome number Signup and view all the answers

An example of autosomal nondisjunction is what?

Down Syndrome Signup and view all the answers

Nondisjunction can also occur in ____________.

sex chromosomes Signup and view all the answers

In ___________, there are extra X chromosomes.

Klinefelter's syndrome Signup and view all the answers

In ____________, females have only one X chromosome.

Turner's syndrome Signup and view all the answers

Biologists can use techniques in molecular biology to _, _____, and even change the DNA code of human genes.

read, analyze Signup and view all the answers

Genetic tests are available to test parents for the presence of _____________ for genetic disorders.

recessive alleles Signup and view all the answers

In a process called __________, individuals can be identified by analyzing sections of DNA that have little or known function.

DNA fingerprinting Signup and view all the answers

These sections of DNA ___________ from one person to the next.

vary widely Signup and view all the answers

In 1990, scientists around the world began the what?

human gene project Signup and view all the answers

The goal was to identify the __________ for entire DNA in a human cell.

DNA sequence Signup and view all the answers

In 2000, the human genome was __________.

sequenced Signup and view all the answers

Now the project goal is to __________ these sequences.

analyze Signup and view all the answers

One way scientists are analyzing the DNA is by looking for ______.

genes Signup and view all the answers

To do this, they look for ______________.

promoter sequences Signup and view all the answers

These are sequences that _______ RNA polymerase.

bind Signup and view all the answers

Information about the human genome can be used to cure genetic disorders by __________.

gene therapy Signup and view all the answers

In one method of gene therapy, a ________ is used to deliver the normal gene into cells to correct the genetic defects.

virus Signup and view all the answers

The virus is changed so that it cannot cause ______.

disease Signup and view all the answers

The normal gene is attached to the ______ of the virus.

DNA Signup and view all the answers

The inserted gene can make ________ that correct the genetic defect.

proteins Signup and view all the answers

There are and with gene therapy.

risks, problems Signup and view all the answers

Having the power to manipulate human DNA doesn't necessarily make it ______.

right Signup and view all the answers

People in a society are responsible for making sure that the tools made available by science are used ______.

wisely Signup and view all the answers

Study Notes

Human Genome Overview

Karyotype: A visual representation of chromosomes arranged in homologous pairs, allows for analysis of human chromosomes.
Humans possess 46 chromosomes: two sex chromosomes (X and Y) and 44 autosomes.
Females have a karyotype of XX, while males have XY.

Inheritance and Genetic Traits

Mendelian principles govern the inheritance of human genes.
Pedigree charts track trait inheritance within families, illustrating familial relationships and specific traits.
Genotype refers to the genetic makeup inferred from pedigree analysis; specific gene associations with traits can be complex.

Human Traits and Genetic Control

Many traits are polygenic, meaning they are influenced by multiple genes.
Environmental factors also affect trait expression.
Blood types (A, B, AB, O) were among the first identified human genes, determined by the presence of A and B antigens.

Blood Group Classification

The ABO blood group system is governed by three alleles: A, B, and O.
Rh factor: Another antigen on red blood cells, classified as Rh positive (having the antigen) or Rh negative (lacking the antigen).
Genetic disorders connected to specific alleles include Phenylketonuria (PKU), Huntington's disease, and sickle cell disease.

Genetic Disorders

PKU arises from a recessive allele; it affects individuals inheriting two copies of this allele.
Huntington’s disease is caused by a dominant allele and expresses in individuals possessing the allele.
Sickle cell disease results from a codominant allele, where both traits influence the phenotype.

Chromosomal Abnormalities

Nondisjunction is a common error during meiosis, leading to abnormal chromosome numbers in gametes.
Examples include Down syndrome (extra chromosome 21) and Klinefelter's syndrome (additional X chromosome).
Turner's syndrome occurs when a female has only one X chromosome.

Genetic Testing and Modification

Genetic tests can identify recessive alleles associated with disorders.
DNA fingerprinting analyzes non-coding DNA sections to identify individuals due to variations.
The Human Genome Project aimed to map and sequence all human DNA, completed in 2000.

Gene Therapy

Gene therapy uses information from the human genome to address genetic disorders.
A modified virus delivers normal genes into cells to correct defects without causing disease.
Ethical implications arise regarding genetic manipulation, emphasizing the need for responsible use of scientific advancements.

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Description

Explore the key terms and concepts related to the human genome in this flashcard quiz. From karyotypes to chromosomes, test your understanding of the fundamental aspects of genetics. Perfect for students looking to enhance their knowledge in biology.