Bio Ch. 10

Front 1

Selective gene expression during development results in _____.

Back 1

differentiation

Front 2

_____ is a multistep process in which abnormally growing and dividing cells disrupt body tissues.

Back 2

Cancer

Front 3

_______ ______ govern the kinds and amounts of substances that are present in a cell at any given time.

Back 3

Gene controls

Front 4

Each cell rarely uses more than ___ percent of its genes at one time

Back 4

10

Front 5

The process by which cells of a multicelled organism become specialized

Back 5

Differentiation

Front 6

_______ occurs as different cell lineages begin to express different subsets of their genes during development

Back 6

Differentiation

Front 7

Gene controls

Back 7

The “switches” that turn gene expression on or off

Front 8

Molecules or structures that start, enhance, slow, or stop the individual steps of gene expression

Back 8

Gene controls

Front 9

Gene control points

Back 9

Front 10

Transcription factor

Back 10

Regulatory protein that influences transcription; e.g., an activator or repressor.

Front 11

Represser

Back 11

Regulatory protein that blocks transcription.

Front 12

Activator

Back 12

Regulatory protein that increases the rate of transcription when it binds to a promoter or enhancer.

Front 13

Enhancers

Back 13

Binding site in DNA for proteins that enhance the rate of transcription.

Front 14

Cascades of ______ ______ govern the development of a complex, multicelled body.

Back 14

gene expression

Front 15

Master gene

Back 15

Gene encoding a product that affects the expression of many other genes.

Front 16

______ ______ encode products that affect the expression of many other genes.

Back 16

Master genes

Front 17

Pattern formation

Back 17

Process by which a complex body forms from local processes during embryonic development.

Front 18

Homeotic genes

Back 18

Type of master gene; its expression controls formation of specific body parts during development.

Front 19

All _____ _______ encode transcription factors with a homeodomain, which is a region of about sixty amino acids that can bind to a promoter or some other sequence of nucleotides in a chromosome.

Back 19

homeotic genes

Front 20

Knockout experiment

Back 20

An experiment in which a gene is deliberately inactivated in a living organism.

Front 21

How do genes control development?

Back 21

Development is orchestrated by cascades of master gene expression in embryos.

The expression of homeotic genes during development governs the formation of specific body parts. Homeotic genes that function in similar ways across taxa are evidence of shared ancestry.

Front 22

____ ____ ____ gives rise to many traits.

Back 22

Selective gene control

Front 23

X chromosome inactivation

Back 23

Shutdown of one of the two X chromosomes in the cells of female mammals.

Front 24

Dosage compensation

Back 24

Theory that X chromosome inactivation equalizes gene expression between males and females.

Front 25

SRY

Back 25

The master gene for male sex determination in mammals

Front 26

Differences in cell types are not due to different genes being present but due to __________ which is the expression of different genes by the cells with the same genome.

Back 26

DIFFERENTIAL GENE EXPRESSION

Front 27

The control of gene expression contributes to two important properties of the cell, which are:

Back 27

1. Cells respond to changes in the internal and external environment by turning genes on and off.
2. The cells of multicellular organism become highly specialized with very specific structure and function.

Front 28

Points of control over gene experssion

Back 28

Control consist of processes that start, enhance, slow or stop gene expression. These controls are
1. Controls of Transcription
2. mRNA Processing
3. mRNA transport
4. Translational control
5. Post translational modification.

Front 29

2 types of transcription factors

Back 29

Activators, Repressors

Front 30

Chemical modifications in gene expression

Back 30

Chemical modifications of DNA affect RNA polymerase’s access to genes

Front 31

DNA METHYLATION

Back 31

Attachment of methyl groups to the cytosine causes DNA to wind tightly around histones preventing transcription.

Front 32

DNA ACETYLATION:

Back 32

Acetyl groups are attached to the lysine in histone tails and prevents them from binding to the neighboring nucleosomes, thus promoting transcription.

Front 33

Alternative splicing (in mRNA processing)

Back 33

Different mRNA molecules are produced from the same primary transcript depending on which exon are spliced out.

Front 34

mRNA localization

Back 34

Delivery within cytoplasm (mRNA localization) – A short base sequence near an mRNA’s Poly A tail is like a ZIP CODE.
Proteins attach to the zip code and drag the mRNA to the particular organelle or area of cytoplasm.
Prevents the RNA from being translated before it reaches its destination.

Front 35

Controls over mRNA stability (translational controls)

Back 35

The life span of mRNA molecules in the cytoplasm is important in determining the pattern of protein synthesis in a cell.

Front 36

RNA INTERFERENCE (translational control)

Back 36

miRNA are short segments of RNA molecules that bind to the mRNA and prevents mRNA from being translated a process called as RNA INTERFERANCE. So expression of miRNA complementary in sequence to a gene inhibits expression of that gene.

Front 37

In eukaryotic cells transcriptional control can operated on at least 3 levels, which are

Back 37

The individual gene
Regions of chromosome
Entire chromosome.

Front 38

The theory that X chromosome inactivation equalizes expression of X chromosome genes between the sexes

Back 38

Dosage compensation

Front 39

Mechanism of X inactivation

Back 39

XIST gene on one X chromosome transcribes an RNA molecule which coats the chromosome and causes it to condense, forming a Barr body

Front 40

X Chromosome inactivation

Back 40

In cells of female mammals, either the maternal or paternal X chromosome is randomly condensed (Barr body) and is inactive
Occurs in an early embryonic stage, so that all descendants of that particular cell have the same inactive X chromosome, resulting in “mosaic” gene expression.

Front 41

The ABC model (flower formation)

Back 41

Three sets of master genes (A,B,C) encode products that initiate cascades of expression of other genes to accomplish intricate tasks such as flower formation
Master genes are expressed differently in tissues of floral shoots
Master genes are switched on by environmental cues such as day length

Front 42

Prokaryotes are single celled and do not have ____ ______

Back 42

master genes

Front 43

Prokaryotes control gene expression mainly by adjusting the______ in response to shifts in _______ and other outside conditions

Back 43

rate of transcription; nutrient availability

Front 44

In ______, genes that are used together often occur together on chromosomes

Back 44

prokaryotes

Front 45

An operon consists of 4 parts, which are

Back 45

A regulatory gene: Which controls the timing or rate of transcription of other genes
A promoter: RNA polymerase binding site
An operator: A binding site for repressor
Structural genes: Genes that encode the enzymes required for lactose breakdown.

Front 46

the lac operon

Back 46

E. coli digest lactose in guts of mammals using a set of three enzymes controlled by two operators and a single promoter (the lac operon)

Front 47

Explain how the lac operon works

Back 47

When lactose is not present, repressors bind to the operators and inactivate the promoter; transcription does not proceed
When lactose is present, allolactose binds to the repressors; repressors don’t bind to operators to inactivate the promoter; transcription proceeds

Front 48

Human infants and other mammals produce the enzyme _____, which digests the lactose in milk

Back 48

lactase

Front 49

ABC genes

Back 49

Front 50

What are some examples of gene control in eukaryotes?

Back 50

X chromosome inactivation balances expression of X chromosome genes between female (XX) and male (XY) mammals.

SRY gene expression triggers the development of male traits in mammals.

In plants, expression of ABC master genes governs development of the specialized parts of a flower.

Front 51

Bacteria control gene expression mainly by adjusting the _______

Back 51

rate of transcription

Front 52

operator

Back 52

Part of an operon; a DNA binding site for a repressor.

Front 53

Operon

Back 53

Group of genes together with a promoter–operator DNA sequence that controls their transcription.

Front 54

Lac operon diagram

Back 54

Front 55

Riboswitch

Back 55

Small sequences of RNA nucleotides that bind to a target molecule.

Front 56

Some bacterial mRNAs regulate their own translation with ______

Back 56

riboswitches

Front 57

Do bacteria control gene expression?

Back 57

In bacteria, the main gene expression controls regulate gene expression in response to shifts in nutrient availability and other environmental conditions.

Prokaryotes can regulate gene expression using operons and riboswitches.

Front 58

__________ and other modifications that accumulate in DNA during an individual's lifetime can be passed to offspring.

Back 58

Methylations

Front 59

Methylation of histone proteins _______ DNA transcription.

Back 59

silences

Front 60

What happens in mRNA processing?

Back 60

Before eukaryotic mRNAs leave the nucleus, they are modified—spliced, capped, and finished with a poly-A tail (Section 9.3). Controls over these modifications can affect the form of a protein product and when it will appear in the cell

Front 61

In eukaryotes, transcription occurs in the _____, and translation in the _______.

Back 61

nucleus; cytoplasm

Front 62

______ are genes that determine which parts of the body form what body parts

Back 62

Homeotic genes

Front 63

DNA acetlyation diagram

Back 63