An overview of genetics

Question 1

What is the study of genetics?

Answer 1

A branch of biology involved in heredity and variation. It is centered on the study of genes, which are the unit of heredity.

Question 2

What is a gene at the molecular level?

Answer 2

A gene is a segment of DNA, it contains information that helps in producing a functional product.

Question 3

What is the functional product of most genes?

Answer 3

The functional product of most genes is a polypeptide.

Question 4

How is DNA formed?

Answer 4

1) Nucleotides linking together and producing a macromolecule known as a DNA chain. (linear sequence of nucleotides)

Question 5

How are chromosomes formed? and where are they located?

Answer 5

The DNA associates with proteins (histones) to form a chromosome. There are 46 chromosomes and 23 pairs of chromosomes.

Chromosomes are located in a membrane bound organelle known as the nucleus.

Question 6

How long is DNA?

Answer 6

2 meters

Question 7

How many protein coding genes do humans have?

Answer 7

Around 22,000. These genes are responsible for performing most life function.

Question 8

How many DNA base pairs per set of chromosomes?

Answer 8

around 3 billion.

Question 9

In what form is DNA found in living cells?

Answer 9

within large structures known as chromosomes.

Question 10

What is a karyotype?

Answer 10

Its a photographic representation of all the chromosomes. it reveals how many chromosomes are within an actively dividing somatic cell.

A karyotype is an individual’s complete set of chromosomes. The term also refers to a laboratory-produced image of a person’s chromosomes isolated from an individual cell and arranged in numerical order. A karyotype may be used to look for abnormalities in chromosome number or structure.

Question 11

what is the difference between somatic cells and gametes?

Answer 11

1) Somatic cells contain all the human 23 pairs of human chromosomes (Autosomes and sex chromosomes)

2) Gametes contain 23 chromosomes (in chromosome 23, Ovas only carry X chromosomes, while sperms carry either X or Y)

Question 12

What is tubulin?

Answer 12

Tubulin is a protein, it is also the building block of microtubules. Microtubules are a part of the cytoskeleton, they are involved in structural support of the cell, cell movement (including intracellular transport), cell division (the mitotic spindle), and organization.

Question 13

What are enzymes?

Answer 13

Proteins that accelerate/catalyze chemical reactions within the cell.

Question 14

What is the difference between catabolic enzymes and anabolic enzymes?

Answer 14

1) Catabolic enzymes are involved in the breakdown of molecules, in reactions that release energy.

2)Anabolic enzymes are involved in the synthesis of molecules, in reactions that require energy.

Question 15

why is the construction of a cell greatly dependent on proteins involved in anabolism?

Question 16

How is DNA involved in protein synthesis?

Answer 16

Genes contain DNA sequences
Most of these sequences contain information that direct the order of amino acids within a polypeptide, this information is in the form of codons. example: ATG codes for methionine.

Question 17

What is the genetic code?

Answer 17

It is a set of codons, each containing three nucleotides. each codon is encoding for an amino acid or a stop sign.

Question 18

what is gene expression?

Answer 18

The transcription of a gene into an mRNA sequence, and the translation of the mRNA into a protein. (usually the product of gene expression is a protein)

Question 19

How does the molecular expression of genes lead to an organisms traits?

Answer 19

The process of gene expression will result in the formation of proteins, and the function of these proteins will affect the organisms trait.

Question 20

The study of genetics encompasses 4 levels of biological organization, what are these levels?

Answer 20

1) molecular level
2) cellular level
3) organismal level
4) populations level

Question 21

At what level are genes expressed ?

Answer 21

At the molecular level

Question 22

What is an allele?

Answer 22

One of two or more versions of a genetic sequence at a particular region on a chromosome. An individual inherits two alleles for each gene, one from each parent.

Question 23

How do different alleles of the same gene result in genetic variation?

Answer 23

Alleles can affect protein functions; for example, one can produce a more functional enzyme while the other will produce a less functional one. Alleles can also affect how much a protein is being made. This leads to different traits.

Question 24

At what level do proteins work?

Answer 24

usually at the cellular level.

Question 25

How do proteins affect cells?

Answer 25

A function of a protein can affect a cells structure and function of that cells.

Question 26

At what levels can traits be observed?

Answer 26

At the organism level, even though these traits are a result of the molecular characteristics of the cells.

Question 27

When can we observe the occurrence of a trait within a species?

Answer 27

at the population level.

Question 28

what happens when a trait predominates a population?

Answer 28

it promotes the reproductive success of the members in the population leading to the evolution of reproductive traits.

Question 29

what is genetic variation?

Answer 29

the differences in inherited traits among individuals within a population. Variation is common within members of the same species (hair color)

Question 30

What causes genetic variation?

Answer 30

changes in the DNA sequence when different types of modifications occur.

Question 31

What types of modifications take place in DNA sequence and lead to variation?

Answer 31

1) genetic mutations: small or large differences in a gene sequence

Major alterations can affect the chromosome structure, leading to large segments being deleted, translocated (attached in a different spot), insertions, or being rearranged.

Organisms can also inherit one too many or one too few chromosomes, or an extra set.
(down syndrome 47 chromosomes because extra chromosome 21)

Question 32

What is a model organism?

Answer 32

Organisms that are studied extensively in labs, they aid in understanding different diseases, phenomena, and the knowledge gained can then be applicable to different species. For example: E.coli, mice, and D.melanogaster (a type of fly)

Question 33

What are the three major fields of genetics?

Answer 33

Transmission, molecular, and population genetics.

Question 34

What is transmission genetics?

Answer 34

The study of inheritance patterns of traits as they are passed down from parents to offspring

Question 35

What is the genetic cross?

Answer 35

A technique used by transmission geneticists. It is when two individuals are selectively bred in order to then analyze the offspring and the traits passed down to it, this can help in understanding the patterns of inheritance.

Question 36

What is molecular genetics?

Answer 36

the biochemical understanding of the hereditary material.

• how genetic material works at a molecular level, the molecular features of DNA and how they affect gene expression, studying mutant genes that have an abnormal function.
• analyzing the effects of loss of function mutations
• explains the role of functional nonmutant genes.

Question 37

What is population genetics?

Answer 37

-The understanding of genetic variation, how the variation is related to the environment of the organism, and its role in evolution.

-scientists in this field developed mathematical theories explaining the prevalence of certain alleles within populations.