Chapter 3: Nature vs Nurture

Which Central European scientist started the modern study of genetics in 1866?

Gregor Mendel

What did the principles Gregor Mendel outlined in his paper guidethe transmission of?

Genetic info from one gen to the next

What organism did Gregor Mendel research on in order to describe Mendelian inheritance?

Pea plants

Although Gregor Mendel could describe the patterns of transmission, he didn’t know…

…about genes

What were the units of inheritance Mendel described called?

Genes

Based on Mendel’s work with pea plants, what did English psychologist and anthropologist Francis Galton conclue about desireable traits?

They can be bred into human beings

Based on Mendel’s work with pea plants, what did English psychologist and anthropologist Francis Galton conclue about undesireable traits?

They could be bred out of human beings

Define eugenics

Certain traits can be bred in or out of human beings

In 1990, with James Watson as its first director, the Human Genome Project undertook the ambitious goal of…

…mapping all the human genes. In 2003, 50 years after Watson and Crick’s discoveries, the map of the human genome was completed (NHGRI, 2018).

Define genome-wide association

A technique studying the whole genome at once to spot gene combinations found throughout the genome that correlate with certain traits and conditions

Define CRISPR

a technique that helps remove, add, or replace specific genes

Define genome editing

A process that removes, adds, or replaces specific genes

With the demise of the eugenics movement, ethical issues in genetics research…

…remain and are focused on the implications of gene manipulation.

Define molecular genetics

a field focused on how genes work within a cell

How many chromosome pairs do each of our cells contain?

23 pairs

In what process does cell growth or repair occur?

Mitosis

What happens to a cell during mitosis

It replicates and splits into two

During mitosis, what happens to the number of chromosomes in a cell when that cell replicates?

the number doubles

During mitosis each of the two cells contain the…

…same information as the parent cell.

In (organism name, fill in the blank), almost 2 trillion cells divide every day.

human beings

Why doesn’t the mitosis process work when egg and sperm cells are formed?

Because each parent can only pass half of their genetic information on

What process forms egg and sperm cells?

Meiosis

Define meiosis

Process in which a cell splits in two with each new cell having only halff the number of chromosomes (23 instead of 46)

Define fertilization

When sperm penetrates an egg

Define zygote

The fertilized egg that results from fertilization

What happens to the sperm’s chromosome strands when fertilization occurs?

they join those from the egg to form 23 match pairs of chromosomes, restoring the diploid state.

When fertilization occurs, the chromosome strands from the sperm join those from the egg to form 23 matched pairs in which genes…

…with the same function pair up.

As you can see in Figure 3.1, in 22 of these pairs of chromosomes (called autosomes) the two chromosomes look…

…very similar.

The 23rd chromosome pair can look…

…similar or different.

What are the names of the chromosomes in the 23rd pair?

X and Y

What does the genetic information in the 23rd pair of chromosomes determine?

The sex of the conception

In the 23rd pair, what chromosomes do women have?

Two X chromosomes.

Why can sperm contain either an X or a Y chromosome?

Because men have an X and a Y chromosome in the 23rd pair.

When the egg and sperm unite, whose contribution of either an X or a Y chromosome in the 23rd position determines the child’s sex?

The man

What is the sex of a conception with an X chromosome from both parents?

Female

What is the sex of a conception with an X and Y chromosome?

Male

In which part of the cell are chromosomes located in?

the nuclei

What are chromosomes composed of?

chains of DNA

Define genome

the complete sequence of nitrogenous bases

Within the sequence of nitrogenous bases are areas that work together to provide…

…the codes needed to assemble proteins

Define proteins

Molecules within cells that control the body’s structure and function

Define genes

Areas within a DNA sequence that provide the instructions for making proteins.