Doktor memeriksa sel itu.

The basic word order is Subject – Verb – Object, just like in English:

• Doktor = subject
• memeriksa = verb
• sel itu = object

So it maps neatly to something like The doctor examines that cell.

Malay usually does not use articles like a, an, or the.

So:

• doktor can mean doctor, a doctor, or the doctor
• sel can mean cell, a cell, or the cell

The exact meaning depends on context.

In this sentence, itu helps make sel more definite, so sel itu is often understood as that cell or sometimes the cell.

In Malay, demonstratives like ini (this) and itu (that) usually come after the noun.

So:

• sel ini = this cell
• sel itu = that cell

This is normal Malay word order.
English says that cell, but Malay says cell that.

Its core meaning is that, but in natural translation it can sometimes feel close to the, depending on context.

So sel itu most directly means:

• that cell

But in some situations, English might translate it more naturally as:

• the cell

This happens because itu can make a noun feel more specific or definite.

Periksa is the root word.
memeriksa is the active verb form built with the meN- prefix.

So:

• periksa = check / inspect / examine (root/base)
• memeriksa = to examine / examines / is examining (active verb)

This meN- prefix is very common in Malay for forming active verbs.

Because the root starts with p, the prefix changes shape and the p drops:

• periksa → memeriksa

This kind of sound change is normal in Malay word formation.

Here it marks memeriksa as an active transitive verb—in other words, the subject is actively doing something to an object.

So in:

• Doktor memeriksa sel itu

the doctor is actively examining something, namely sel itu.

Many Malay verbs with meN- take a direct object like this.

Malay verbs usually do not change form for tense the way English verbs do.

So memeriksa by itself does not specifically mean only:

• examines
• is examining
• examined
• will examine

The time is usually understood from context, or shown with time words such as:

• semalam = yesterday
• sekarang = now
• esok = tomorrow
• sudah / telah = already
• akan = will

Without extra time marking, this sentence is often translated in a general present way, such as The doctor examines/is examining that cell, but context decides.

Yes. On its own, doktor can mean:

• a doctor
• the doctor
• sometimes just doctor as a role or profession

Malay leaves this open unless context makes it specific.

So Doktor memeriksa sel itu could be understood as:

• A doctor is examining that cell
• The doctor is examining that cell

depending on the situation.

By default, sel itu is usually understood as singular: that cell.

Malay nouns do not change form for plural the way English often does.
If speakers need to show plurality clearly, they can use context, numbers, or reduplication.

For example:

• sel-sel itu = those cells
• dua sel itu = those two cells

Without that, sel itu normally reads as singular in a sentence like this.

Yes:

• Doktor memeriksa sel.

That would be more general and less specific, something like:

• The doctor examines a cell
• The doctor is examining cells / a cell

Adding itu makes the object more specific:

• sel itu = that cell / the cell

So itu helps point to a particular one.

Yes, it is a complete and natural sentence.

It has all the core parts:

• subject: Doktor
• verb: memeriksa
• object: sel itu

Malay often allows short, clean sentences like this without extra words that English would require, especially articles like the or a.

Doktor is a standard Malay word, borrowed historically but fully normal in modern Malay.

It is the usual word for doctor, and its spelling follows Malay conventions:

• English: doctor
• Malay: doktor

So this sentence sounds completely ordinary and natural in Malay.

Yes. You could say:

• Dia memeriksa sel itu.

That means:

• He/She is examining that cell

Malay does not mark gender in dia, so it can mean he or she.

Using Doktor instead of dia simply names the subject more specifically.