Chapter 5

Question 1

what are chains of amino acids?

Answer 1

proteins

Question 2

DNA consists of ?

Answer 2

two phosphate backbones joined by a series of bases

Question 3

Which base belongs to with complimentary base: A,T,C,G

Answer 3

A - T
C - G

Question 4

Concept to remember

When a cell divides, the strands of DNA are separated and new complementary strands are added. As a result, the two new DNA strands are identical to the original one

Question 5

how do cells expose or hide genes?

Answer 5

by winding and unwinding DNA around histones

Question 6

what is the number of copies of unique chromosomes in a cell?

Answer 6

Ploidy

Question 7

_______ is the number of different chromosomes in a gamete cell (n)

In _______ organisms, this number is doubled in somatic cells (2n) because _________

Triploid and tetraploid organisms have 3n and 4n chromosome copies in their somatic cells, respectively, and many plants have even higher ploidy numbers.

Answer 7

• Haploidy (n)
• Diploid (2n) because there are two copies of each of the unique chromosomes

Question 8

how many chromosomes do humans have?

Answer 8

22

Question 9

females have paired _ chromosomes, and males have a ___ _ chromosome and a ___ _ chromosome.

Answer 9

females have paired x chromosomes, and males have a single X chromosome and a single** Y** chromosome.

Question 10

Ribosomes translate ____ into ____.

Answer 10

mRNA into protein

Question 11

Concepts to remember

Each messenger RNA molecule acts as a template for building a protein. The ribosome reads three bases at a time (a codon), and a transfer RNA “hooks on” the correct amino acid.

Question 12

Edit

Bacteria have small regulatory sequences near protein-coding regions where proteins can bind, promoting or repressing the expression of those genes. Eukaryotic genes have much more complex mechanisms for gene regulation: their activators, transcription factors, and other molecules cooperate to promote a gene’s expression.

Question 13

what is the purpose of MicroRNA’s and what does it lead to and can block?

Answer 13

They prevent genes from being translated by binding to the mRNA, leading to their degradation

can block translation

Question 14

A group of proteins called the ______ removes _____ before ______, and it can remove some exons as well.

By regulating which ______ are included in the final mRNA transcript, cells can generate many proteins from a single gene. This process is called ______ ______.

Answer 14

A group of proteins called the spliceosome removes introns before translation, and it can remove some exons as well.

By regulating which exons are included in the final mRNA transcript, cells can generate many proteins from a single gene. This process is called alternative splicing.

Question 15

Proteins have diverse functions and changes can affect. What are they?

Answer 15

–Cell structure
–Ability to catalyze enzymatic reactions
–Cell to cell signaling
–Ability to respond to other molecules

Question 16

____ to DNA can alter the structure of proteins

Answer 16

mutations

Question 17

what kind of mutation affect cells in the body of an organism; not heritable?

Answer 17

somatic mutations

Question 18

what kind of mutation affect gametes; heritable and relevant to evolution?

Answer 18

germ-line mutations

Question 19

Different mutations arise in humans at different rates.

While small mutations are more common, large mutations end up _________________?

Answer 19

introducing more mutated bases into a population

Question 20

Germ-line mutations are rare, but accumulate in populations over time

they are the raw material for what?

Answer 20

evolution

Question 21

In diploids, ______ __ may be masked by the presence of a ____ ____ ____ ____ ____ on the other chromosome

Answer 21

In diploids, deleterious mutations may be masked by the presence of a functional copy of the gene on the other chromosome

Question 22

**Concept to remember **

Genetic changes in gene expression arise when noncoding mutations affect where, when, and how much a gene is transcribed

Question 23

Among sexually reproducing organisms, like humans, males and females combine their gametes to reproduce.

During the production of gametes, each pair of chromosomes crosses over and exchanges segments of DNA, in a process known as what?

Answer 23

genetic recombination (crossing over)

Question 24

Each gamete receives only one copy from each pair of chromosomes. As a result, each child carries a unique combination of the DNA of his or her parents. Along with independent assortment (next slide), ——– increases genetic diversity by producing ——–.

Answer 24

recombination

novel combinations of alleles

Question 25

what occurs during meiosis in sexually reproducing eukaryotic organisms and produces gametes with a mixture of maternal and paternal chromosomes

Answer 25

independent assortment

Question 26

what generates considerable genetic variation and its two techniques?

Answer 26

Meiosis

• Recombination
• Independent assortment

Question 27

what results in great genetic diversity among offspring?

Answer 27

fusion of egg and sperm

Question 28

**Linking genotype and phenotype
**

——: the genetic make-up of an individual
——: an observable measurable characteristic of an organism

Answer 28

• Genotype
• Phenotype

Question 29

what is a result of an organism’s genotype and the environment?

Answer 29

Phenotypes

Question 30

what often result from a developmental threshold mechanism?

Answer 30

Polyphenisms

Answer 31

quantitative traits

Question 32

Study of their inheritance and evolution is called ——

Answer 32

quantitative genetics

Question 33

Evolutionary biologists study variation in the ——–

Answer 33

expression of phenotypic traits

Question 34

**Environmental Influences on Gene Expression
**

what changes in phenotype produced by a single genotype in different environments?

Answer 34

Phenotypic plasticity
- tailors organisms to environment

Question 35

Phenotypic Plasticity is not the same as Natural Selection. PP is the flexibility for a population to show a —- term response to ——. NS is a —– term change in genes that allows a long-term response to ——- stimuli.

Answer 35

PP is the flexibility for a population to show a short-term response to stimuli. NS is a long-term change in genes that allows a long-term response to changing stimuli.

Question 36

Gene expression often influenced by what?
and allows match to what?

Answer 36

Gene expression often influenced by signals from the environment

Allows match to environmental circumstances

Question 37

what is natural selection?

Answer 37

mechanism that can lead to evolution, whereby differential survival and reproduction of indiciauls cause some genetic types to replace (outcompete) others

Question 38

character state similarity not due to common descent

Answer 38

homoplasy

Question 39

——: independent evolution of similar trait
——: reversion back to an ancestral character state

Answer 39

Convergent evolution

Evolutionary reversals

Question 40

Principle of Maximum Parsimony

Answer 40

The alternative requiring the fewest evolutionary steps is usually best.
If more than one tree is equally parsimonious we can construct a Consensus Tree

Question 41

Feathers are an ——–; they evolved originally for functions other than flight

Answer 41

Feathers are an exaptation; they evolved originally for functions other than flight

Question 42

Pseudogenes are —–

Answer 42

Non-functional

Question 43

**Concept to remember **

In genetics, a centimorgan (abbreviated cM) is a unit for measuring genetic linkage. It is often used to infer distance along a chromosome. However, it is not a true physical distance.

Question 44

what kind of process is natural selection?

Answer 44

the process in nature by which organisms better adapted to their environment tend to survive and reproduce more than those less adapted to their environment

Question 45

Survival in the struggle for existence is not random but depends in part on the hereditary constitution of the survival individuals. This unequal survival constitutes the process of natural selection. Over the generations this process of natural selection will lead to a continuing gradual change of populations, that is, to evolution and to the production of new species.