BIO 102: EXAM 2 STUDY GUIDE,
2025/2026 WITH
CORRECT/ACCURATE ANSWERS
Skeleton and Muscles
1. Define skeleton and muscles.
a. Skeleton: provides support and anchor points for muscles
b. Muscles: Contract to produce force
2. Define the different types of muscles and give examples of animals
that may have them.
a. Hydrostatic skeleton: fluid squeezed between two layers,
cnidarians and worms
b. Exoskeleton: hard outer covering, arthropods
c. Endoskeleton: internal skeleton, usually bone but
sometimes cartilage, mammals
3. Define bone and cartilage and describe what it is composed of both
microscopically and visibly.
a. Bone: and organ of the vertebrate skeleton system, comprised of
hardened ECM and other cells, cartilage cushions the edges
b. Compact Bone: more solid areas of bone, found along the edges
of long bones
c. Spongey Bone: obviously porous areas of bone
d. Marrow: fills the “empty” spaces, makes blood cells
4. Describe the cells and minerals that comprise bones and make it hard.
a. Osteocytes: a cell that produces bony ECM
b. Matrix (ECM): collagen and minerals, mostly calcium
and phosphate
c. The minerals, mainly calcium, mostly makes bones hard
5. What happens when calcium in the blood is too low? Describe what
kind of feedback this is.
a. When calcium in the blood is low, a hormone will
promote calcium to move from bones into blood
b. Osteoporosis: thinning of bone from calcium loss
c. Negative Feedback
6. Define and describe joints, ligaments, and tendons.
, a. Joints: where two bones meet
b. Ligaments: dense connective tissue linking bone to bone
c. Tendons: dense connective tissue linking bone to muscle
7. Describe skeletal muscles.
a. Skeletal muscle tissue: voluntary muscle attached to skeleton,
dense striations, move the skeleton
, 8. Do muscles pull or push? Describe antagonistic pairs and give
examples.
a. Muscles pull
b. Antagonistic Pairs: muscles that work opposite one
another, (biceps contract, triceps relax)
9. Describe muscle fiber and sarcomeres.
a. Muscle fibers: one muscle cell, long and thin, strips go opposite
of contraction
b. Sarcomere: the smallest contractile unit of a muscle, groups of
protein smaller than a cell
10. Compare and contrast thick filaments, thin filaments, and the Z- line.
a. Thick filaments: the middle of the sarcomere
b. Thin filaments: reach from the edges of the sarcomere
c. Z-line: the edge of the sarcomere
11. Define cytoskeleton:
a. Protein structures inside the cell that provide a cell shape and
allow movement
12. What are actin and myosin? Describe their roles in muscle
contraction.
a. Actin: the major protein in thin filaments, a cytoskeleton
filament, “tracks”
b. Myosin: the major protein in thick filaments, motor
protein, “train”
2025/2026 WITH
CORRECT/ACCURATE ANSWERS
Skeleton and Muscles
1. Define skeleton and muscles.
a. Skeleton: provides support and anchor points for muscles
b. Muscles: Contract to produce force
2. Define the different types of muscles and give examples of animals
that may have them.
a. Hydrostatic skeleton: fluid squeezed between two layers,
cnidarians and worms
b. Exoskeleton: hard outer covering, arthropods
c. Endoskeleton: internal skeleton, usually bone but
sometimes cartilage, mammals
3. Define bone and cartilage and describe what it is composed of both
microscopically and visibly.
a. Bone: and organ of the vertebrate skeleton system, comprised of
hardened ECM and other cells, cartilage cushions the edges
b. Compact Bone: more solid areas of bone, found along the edges
of long bones
c. Spongey Bone: obviously porous areas of bone
d. Marrow: fills the “empty” spaces, makes blood cells
4. Describe the cells and minerals that comprise bones and make it hard.
a. Osteocytes: a cell that produces bony ECM
b. Matrix (ECM): collagen and minerals, mostly calcium
and phosphate
c. The minerals, mainly calcium, mostly makes bones hard
5. What happens when calcium in the blood is too low? Describe what
kind of feedback this is.
a. When calcium in the blood is low, a hormone will
promote calcium to move from bones into blood
b. Osteoporosis: thinning of bone from calcium loss
c. Negative Feedback
6. Define and describe joints, ligaments, and tendons.
, a. Joints: where two bones meet
b. Ligaments: dense connective tissue linking bone to bone
c. Tendons: dense connective tissue linking bone to muscle
7. Describe skeletal muscles.
a. Skeletal muscle tissue: voluntary muscle attached to skeleton,
dense striations, move the skeleton
, 8. Do muscles pull or push? Describe antagonistic pairs and give
examples.
a. Muscles pull
b. Antagonistic Pairs: muscles that work opposite one
another, (biceps contract, triceps relax)
9. Describe muscle fiber and sarcomeres.
a. Muscle fibers: one muscle cell, long and thin, strips go opposite
of contraction
b. Sarcomere: the smallest contractile unit of a muscle, groups of
protein smaller than a cell
10. Compare and contrast thick filaments, thin filaments, and the Z- line.
a. Thick filaments: the middle of the sarcomere
b. Thin filaments: reach from the edges of the sarcomere
c. Z-line: the edge of the sarcomere
11. Define cytoskeleton:
a. Protein structures inside the cell that provide a cell shape and
allow movement
12. What are actin and myosin? Describe their roles in muscle
contraction.
a. Actin: the major protein in thin filaments, a cytoskeleton
filament, “tracks”
b. Myosin: the major protein in thick filaments, motor
protein, “train”
