cell structure

Question 1

prokaryotes vs Eukaryotes

Answer 1

Pro: No nucleus, no membrane bound organelles, smaller, single celled

Euk : have a nucleus, membrane bound organelles, can be unicellular or multicellular

Question 2

Plants vs Animal Cells

Answer 2

Plants: have a chloroplasts, a central vacuole, and a cell wall

animals: have lysosomes, centrioles but lack chloroplasts and cell walls

Question 3

Organelles and their functions

Answer 3

nucleus: stores genetic materal ( DNA)
ribosomes: protein synthesus ( found in both pro and euk)

endoplastic reticulum:

rough ER : has ribosomes; syntehsiszes proteins

smooth ER: no ribosomes; lipid syntehsis, carb metabolism, detox

Golgi Apparatus: modies, sorts and packages proteins for transport

Vacuoles:
food vac: formed by phagocytosis
central vac: large in plants for stroage and maintaining turgor pressure

Lysosomes: contain digestive enzymes; breakdown of wst

mitochondria: converts sugar and oxygen into ATP (cell respiration)

Choloroplasts: conduct photosynthesis( found in plants)

Question 4

Endosymbiont theory

Answer 4

mitochondira and cholorplasts wer once indepents prokaryotic cells that were engulfed by ancestral eukaryotic cells

evidence:
double memrbane
own circular DNA
own ribosomes
independant reproduction

Question 5

Cytoskeleton

Answer 5

microtubles: cell shape, movements of organelles, spindle fibers in mitosis

microfilaments: Actin filaments of cell movement, shape and division

intermediate filaments: structural support, anchoring organelles

Question 6

Define the endosymbiont theory and describe at least three pieces of evidence supporting it.

Answer 6

The endosymbiont theory states that mitochondria and chloroplasts originated as independent prokaryotic cells that were engulfed by a larger cell. Evidence includes: (1) They have double membranes, (2) They contain circular DNA, (3) They have their own ribosomes similar to prokaryotes, (4) They reproduce independently.

Question 7

Describe how the cytoskeleton contributes to both cell structure and movement. Give specific examples of how microtubules, microfilaments, and intermediate filaments function in the cell.

Answer 7

The cytoskeleton maintains cell shape, allows intracellular transport, and enables movement. Microtubules form spindle fibers and cilia, microfilaments support cell division and movement, and intermediate filaments provide structural stability.

Question 8

The mitochondria are often referred to as the “powerhouse of the cell.” Explain how mitochondria generate energy for the cell and why they are essential for cellular function.

Answer 8

Mitochondria break down glucose in the presence of oxygen through cellular respiration to generate ATP, which is essential for cellular energy needs.