У охраны есть список гостей.

Russian often expresses possession with the pattern у + Genitive + (есть) + Nominative:

• У охраны = literally at/with the security
• есть = there is / exists (often omitted in the present)
• список = the thing that exists/ is available “with them”

So У охраны есть список гостей is literally With security there exists a guest list, i.e. Security has a guest list.

у basically means at, by, near; in someone’s possession / under someone’s control.
After у, the noun goes in the genitive case, so:

• охрана (nominative) → охраны (genitive)

That’s why it’s У охраны, not У охрана.

охрана is a collective/organizational noun meaning security (service/staff), like “security” in English. It doesn’t necessarily refer to one person.

If you mean a single guard, you’d usually say:

• охранник = (male) security guard
• охранница = (female) security guard
  Example: У охранника есть список гостей = The guard has a guest list.

есть here signals existence/availability in the present. In many everyday sentences it’s optional:

• У охраны есть список гостей. (neutral, explicit)
• У охраны список гостей. (also common; slightly more “matter-of-fact”)

You normally keep есть when you want to stress that it does exist/they do have it, or in more careful speech.

Because список (a list) typically takes the genitive to show what the list is of:

• список гостей = a list of guests

So гостей is genitive plural of гость (guest). Dative (гостям) would mean “to/for the guests,” which doesn’t fit here.

список is nominative singular because it’s the thing being stated as existing/available:

• У охраны есть (что?) список.
  In this possession pattern, the possessed item is typically in the nominative when using есть.

Russian uses нет and switches the possessed item to the genitive:

• У охраны нет списка гостей.

Key changes:

• есть → нет
• список (nom.) → списка (gen.)

Two very common ways: 1) Intonation only:

• У охраны есть список гостей? = Does security have a guest list? 2) Using ли (more explicit):
• Есть ли у охраны список гостей? = Is there a guest list with security? / Does security have a guest list?

Russian has no articles, so список гостей can mean a guest list or the guest list depending on context.

If you want to emphasize “the specific one,” you might add a demonstrative:

• У охраны есть этот список гостей. = Security has this (particular) guest list.

Word order is flexible and changes emphasis:

• У охраны есть список гостей. (neutral: “security has it”)
• Список гостей есть у охраны. (emphasizes that the guest list is with security, not elsewhere)
• У охраны есть список гостей, а у администратора — нет. (contrast: security has it; the administrator doesn’t)

The grammar stays the same; the focus shifts.

Common stresses:

• охрАна
• спИсок
• гОстей

So: У охрАны есть спИсок гОстей.