Thick or dense smears less likely to provide a good smear preparation for microscopic because it will diminish the amount of light that can pass through making it difficult to visualize the morphology of single cells under the microscope. Some times the stain can't penetrate all of the bacteria.
<h3 /><h3>What is a microscopic smear?</h3>
- A smear is a microscopic specimen.
- A swab or loop, or the edge of another slide, is used to spread the sample to be examined, such as blood or microbial culture, thinly and unevenly across the slide.
- Smear preparation involves spreading a small amount of sample on a slide and air drying the film before staining and microscopy.
- The conventional method, blood film method, drop and rest method, and water-wash method are the four types of smearing methods.
- Smear microscopy entails collecting a biological sample (typically sputum or other clinical material), fixing it thinly on a glass slide, and staining it with a dye that binds specifically to mycobacteria (making them easier to identify under a microscope).
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Answer:
The correct answer would be C) The Calvin cycle takes place only in the chloroplast.
The major difference between photosynthesis and respiration is that photosynthesis takes place only in plants while respiration takes place in all the living organisms including plants and humans.
Green plants and few bacteria contain special organelle called chloroplast which enables them to perform photosynthesis.
Hence, Calvin cycle (light independent phase of photosynthesis) takes place only in plants that too in chloroplasts.
In contrast, Krebs cycle usually takes place in mitochondria in both plants and animals and glycolysis takes place in the cytoplasm of the cell.
The electron transport chain takes place in mitochondria in animals whereas in plants it takes place in both mitochondria and thylakoid membrane.
Population Growth - Basic Information
All populations change in size with time
- if births exceed deaths, the population grows
- if deaths exceed births, the population shrinks
- only when births equal deaths does the population stay the same
Other Population Growth Factors
Populations can also change size if organisms move in (immigration) or leave (emigration)
Putting It All Together
We can write a simple equation to show population growth as:
Change in Population Size = (Births + Immigration) - (Deaths + Emigration)
Expressing Population Changes as a Percentage
Suppose we had a population of 100,000 individuals. Suppose in one year there were 1000 births, and 500 deaths.
What percentage of the population were births?
1000/100,000 = 0.01, or in percentage terms, this is 1% of the population.
What percentage of the population were deaths?
500/100,000 = 0.005, or in percentage terms, this is 0.5% of the population.
Assume immigration equals emigration. If so, then they cancel out of our population equation. We'll come back to
this assumption later.
Now, subtract deaths from births but express as a percentage:
1000-500/100,000 = 500/100,000 = 0.005, or 0.5% net growth
Thus, this population would be growing by 0.5% this first year. That means that after one year, there will be 500 more
individuals than the previous year. So, after one year, the population would be 100,500 individuals.
The Net Reproductive Rate
The net reproductive rate (r) is the percentage growth after accounting for births and deaths. In the example above, the population reproductive rate is 0.5%/yr.
Net reproductive rate (r) is calculated as: r = (births-deaths)/population size or to get in percentage terms, just multiply by 100.
Suppose we came back many years later, the net reproductive rate was still the same, but now the population had grown to 1,000,000. How many new individuals would be added each year now? Simply multiply the population by the reproductive rate:
1,000,000 x 0.05 (which is 0.5%) = 50,000
This means that now 50,000 new individuals are added in one year!! The net reproductive rate is the same as before, but because
the population is so much bigger, many more individuals are added.
Exponential Growth
If a population grows by a constant percentage per year, this eventually adds up to what we call exponential growth. In other words, the larger the population grows, the faster it grows!! A curve of exponential growth is an upward sweeping growth curve.
Answer:
The modern evolutionary synthesis defines evolution as the change over time in this genetic variation. The frequency of one particular allele will become more or less prevalent relative to other forms of that gene.
Explanation:
A substantial part of the phenotypic variation in a population is caused by genotypic variation.
