A bolsa de sangue tem plasma e plaquetas.

A is the definite article: the. So a bolsa means the bag.

If you wanted a/an bag, you would say uma bolsa.

• a bolsa = the bag
• uma bolsa = a bag

In this sentence, a bolsa de sangue sounds like a specific, already identified blood bag.

Because bolsa is a feminine noun in Portuguese, so it takes the feminine article a.

• a bolsa
• not o bolsa

Many nouns ending in -a are feminine, and bolsa is one of them.

De usually means of. Here, bolsa de sangue literally means bag of blood.

This noun + de + noun pattern is very common in Portuguese:

• copo de água = glass of water
• barra de chocolate = chocolate bar
• bolsa de sangue = blood bag

So de sangue tells you what kind of bag it is.

It stays singular because it names the substance/material, not individual countable items.

So Portuguese says:

• bolsa de sangue
• copo de água
• garrafa de vinho

Even in English, we usually do the same: a bag of blood, not a bag of bloods.

Tem is the third-person singular form of the verb ter.

Here the subject is a bolsa de sangue, which is singular, so the verb must also be singular:

• A bolsa ... tem ... = The bag has ...

A quick comparison:

• ela tem = she/it has
• elas têm = they have

So tem is correct because bolsa is singular.

They come from the same verb, ter, but they match different subjects:

• tem = singular → he/she/it has
• têm = plural → they have

Examples:

• A bolsa tem plasma.
• As bolsas têm plasma.

Notice the accent in têm. It helps show that the subject is plural.

Yes. In everyday Brazilian Portuguese, ter is very commonly used where English might say has or contains.

So A bolsa de sangue tem plasma e plaquetas sounds natural.

If you want a more formal or technical verb, you could also say:

• A bolsa de sangue contém plasma e plaquetas.

Both are correct, but tem is simpler and very common.

Portuguese often leaves out articles when listing substances or components in a general way.

So:

• tem plasma e plaquetas

sounds natural as it has plasma and platelets.

You could sometimes include articles in other contexts:

• tem o plasma e as plaquetas separados
• foram analisados o plasma e as plaquetas

But in a simple statement of contents, leaving them out is normal.

Because they are two different things, so Portuguese lists them separately and joins them with e = and.

• plasma = singular noun
• plaquetas = plural noun

This is exactly how English works too: plasma and platelets.

Yes. Contém means contains, and it is more formal or technical.

So these are both correct:

• A bolsa de sangue tem plasma e plaquetas.
• A bolsa de sangue contém plasma e plaquetas.

In everyday speech, tem is more common. In medical, scientific, or written contexts, contém may sound more precise.

In Brazilian Portuguese, tem is pronounced with a nasal sound at the end, roughly like teyn with the ending nasalized.

A rough English-friendly approximation is:

• tem ≈ tehng / teyn (nasal)

It is not a strong final m sound like in English. The m mainly nasalizes the vowel.

Yes, but the original order is the most neutral and straightforward.

Neutral version:

• A bolsa de sangue tem plasma e plaquetas.

A different order might be used for emphasis:

• Na bolsa de sangue, tem plasma e plaquetas.

That second version is possible in speech, but the original sentence is better for standard, clear structure: subject + verb + contents.

E is the conjunction and.

It connects the two nouns:

• plasma e plaquetas

This is exactly like English plasma and platelets.