Why should the agar plate be sterile before the bacteria are placed on it

The shape of a protein molecule resembles _____. A. beads on a string B. a messy group of coat hangers C. a flat stack of straig

Sindrei [870]

The correct answer is The shape of a PROTEIN molecule resembles a messy group of coat hangers.

To function, proteins must have the necessary amino acids in a specific sequence and be folded into a specific shape. A sequence is a continuous series. Proteins loop, coil, and crinkle into complicated shapes. The shapes appear more like messy groups of wire coat hangers than stacks of neatly folded dish towels.

7 0

4 years ago

Read 2 more answers

when male and female gamete are produced by different parents unite to form zygote this type of reproduction is termed

riadik2000 [5.3K]

Answer:

Sexual reproduction.....

5 0

3 years ago

For this assignment you will complete an illustration(s) (by hand) of how the lac operon works. You should be sure to include de

Fantom [35]

<h2>Lac operon </h2>

Explanation:

Lac operon present in prokaryotic chromosomes whose product involves in transportation and catabolism of lactose

Lac operon consists of three structural genes called Lac Z,Lac Y and Lac A and a regulatory element(promoter and operator)
Lac I gene is present outside the Lac operon,act as regulatory gene and control the expression of Lac operon genes
Lac Z codes for β galactosidase which converts lactose into allolactose
Lac Y codes for Lac permease which act as a membrane transporter and transport lactose into the cells
Lac A codes for transacetylase which neutralize the toxic effects of lactose

Lac operon in absence of lactose

In absence of lactose Lac operon exists in switch off state
Lac I gene produces Lac repressor which binds to operator region and prevent binding of RNA Polymerase thus blocks transcription

Lac operon in presence of lactose

In presence of lactose Lac operon exists in switch on state
In presence of lactose few molecules of Lac operon enzyme catalyse conversion of lactose to allolactose
Allolactose act as an inducer,binds to the Lac repressor and induce conformational changes causing dissociation of Lac repressor from operator
In absence of Lac repressor RNA Polymerase binds to the promoter and starts transcription of genes which catabolize lactose

Lac promoter is a weak promoter and direct transcription of Lac operon genes in very low level in presence of lactose

For higher level expression of Lac operon genes,operon system require conversion of weak promoter to strong promoter which is always mediated by catabolite protein-cAMP complex(CAP-cAMP complex)
CAP cAMP complex binds to the upstream of promoter called CAP binding site and stimulate expression of Lac operon genes by facilitating binding of RNA Polymerase
Catabolite activator protein(CAP) or cAMP receptor protein(CRP) activate when cAMP binds
cAMP is a secondary messenger synthesized from ATP and act as co-activator of CRP
With respect to CAP cAMP complex Lac operon system is positively controlled
In prokaryotic cell cAMP is very low when glucose concentration is relatively high and vice versa
At high concentration of glucose the growth rate is maximum and lactose catabolism is repressed called catabolite repression

6 0

3 years ago

As a general rule, it takes people between the ages of 20 and 29 two weeks to adapt to a cardiorespiratory activity workload.

Maru [420]

Answer:

As a general rule, it takes people between the ages of 20 and 29 two weeks to adapt to a cardio-respiratory activity workload.

True

Explanation:

Cardio-respiratory activities are those activities which are done to provide strength to our heart and lungs. These activities include running, bicycling and swimming.
It takes only two weeks for the people of ages between 20 and 29 to make them comfortable in a cardio-respiratory activity.
There are four components of the cardio-respiratory activities/ training:

Frequency
Intensity
Time
Type

5 0

4 years ago

Cellular respiration takes place primarily in organelles called mitochondria. Some textbooks claim that "Mitochondria make the e

tigry1 [53]

Actually, the mitochondria does not MAKE the energy, it just makes it usable to the cell! It is through cellular respiration that this can take place.

Thank you for the opportunity to respond to you, and I hope this helped. I wasn't exactly sure what you were asking... if you would like more help, I would be more than happy to assist you!!!

8 0

3 years ago