Chapter 3: Genetics and Genomics: Reproducing Life and Producing Variation

Question 1

What is genetic code?

Answer 1

DNA packaged in chromosomes

Nuclear DNA provides most genetic code

Question 2

What does genetic code (DNA) do?

Answer 2

1. Serves as the chemical template for its own replication and the creation of proteins
2. First step in cell reproduction

Question 3

What is the genetic basis for human variation?

Answer 3

1. Genes are linear sequences of nucleotides that code for specific body structures and functions
2. Each gene has a locus on each chromosome
3. Each pair of chromosomes has a paternal and a maternal chromosome
4. Genotypes are pased on two alleles and are expressed physically as phenotypes
5. Most physical characteristics rely on multiple genes

Question 4

Amino acids

Answer 4

Organic molecules combined in a specific sequence by the ribosomes to form a protein

Question 5

Autosomes

Answer 5

All non-sex chromosomes that occur in pairs in all somatic cells

Question 6

Codons

Answer 6

The sequences of 3 nitrogen bases carried by mRNA that are coded to produce specific amino acids in protein synthesis

Question 7

Crossing-over

Answer 7

Process by which homologous chromosomes partially wrap around each other and exchange genetic info during meiosis

Question 8

Diploid

Answer 8

Cell with a full complement of paired chromosomes

Question 9

Epigenetic

Answer 9

Refers to chemical changes in the genome affecting how the underlying DNA is used in production of proteins, but without altering the DNA sequences

Question 10

Gametes

Answer 10

Sexual reproductive cells, contain haploid number of chromosomes

Pair with other gametes during reproduction to form new organism

Question 11

Genome

Answer 11

Complete set of genetic information for an organism or species that represents all inheritable traits

Question 12

Haploid

Answer 12

Cell that has a single set of unpaired chromosomes

Question 13

Haplogroups

Answer 13

Large set of haplotypes that may be used to define a population

Question 14

Heterozygous

Answer 14

Condition in which the two alleles of a pair are different

AB for example

Question 15

Homeotic (Hox) genes

Answer 15

Responsible for differentiating the specific segments of the body, such as the head, tail, and limbs, during embryological development

Question 16

Homologous

Answer 16

Refers to each set of paired chromosomes in the genome

Question 17

Homoplasmic

Answer 17

Refers to nuclear DNA, which is identical to the nucleus of each cell type

Question 18

Homozygous

Answer 18

Condition in which the two alleles of a pair are the same

AA or aa for example

Question 19

Karyotype

Answer 19

Characteristics of the chromosomes for an individual organism or a species such as number, size, and type

Typically presented as a photograph of someone’s chromosomes that have been arranged in homologous pairs and put in numeric order by size

Question 20

Law of independent assortment

Answer 20

Mendel’s second law, which asserts that the inheritance of one trait does not affect the inheritance of other traits

Question 21

Law of segregation

Answer 21

Mendel’s first law, which asserts that the two alleles for any given gene (or trait ) are inherited, one from each parent; during gamete production, only one of the two alleles will be present in each ovum or sperm.

Question 22

Locus

Answer 22

Location on a chromosome of a specific gene

Question 23

Meiosis

Answer 23

Production of gametes through one DNA replication and two cell (and nuclear) divisions, creating four haploid gametic cells

Question 24

Microsatellites

Short tandem repeats STRs

Answer 24

Sequences of repeated base pairs of DNA, usually no more than 2-6

If repeated excessively, they are often associated with neurologic disorders like Huntington’s chorea

Question 25

Mitochondria

Answer 25

Organells with their own DNA that produce energy ATP

Question 26

Mitosis

Answer 26

Process of cellular and nuclear division that creates two identical diploid daughter cells

Question 27

Nondisjunctions

Answer 27

Failure of the chromosomes to properly segregate during meiosis, creating some gametes with abnormal numbers of chromosomes

Question 28

Nucleotide

Answer 28

Building block of DNA and RNA, composed of sugar, phosphate group, and one of four nitrogen bases (A, T, G, C)

Question 29

Pleiotropy

Answer 29

A single gene can have multiple effects

Question 30

Polygenic

Answer 30

One phenotypic trait is affected by 2+ genes

Question 31

Polymorphism

Answer 31

Refers to the presence of two or more alleles at a locus and where the frequency of the alleles is greater than 1% in the population

Question 32

Recombination

Answer 32

Exchange of genetic material between homologous chromosomes due to a crossover event

Question 33

Regulatory genes

Answer 33

Determine when structural genes and other regulatory genes are turned on/off for protein synthesis

Question 34

Replication

Answer 34

Process of copying nuclear DNA prior to cell division so that each new daughter cell receives a complete complement of DNA

Question 35

Ribonucleic acid RNA

Answer 35

Single-strand molecule involved in protein synthesis, consissts of phosphate, ribose sugar, and one of four N bases

Question 36

Ribosomes

Answer 36

Organelles attached to the surface of the endoplasmic reticulum, located in the cytoplasm of a cell Site of protein synthesis

Question 37

Sex chromosomes

Answer 37

Pair of chromosomes that determine biological sex | XX or XY

Question 38

Single nucleotide polymorphisms SNPs

Answer 38

Variations in the DNA sequence due to the change of a single N base

Question 39

Somatic cells

Answer 39

Diploid cells that form organs, tissues, and other body parts

Question 40

Structural genes

Answer 40

Genes coded to produce particular enzymes, hormones, etc.

Question 41

Transcription

Answer 41

1st step of protein synthesis, involves creation of mRNA based on the DNA template

Question 42

Translation

Answer 42

2nd step of protein synthesis, involves transfer of amino acids by tRNA to the ribosomes, which are then added to the protein chain

Question 43

Translocations

Answer 43

Rearrangements of chromosomes due to the insertion of genetic material from one chromosome to another

Question 44

Zygote

Answer 44

The cell that results from egg fertilization