biology

Question 1

define asexual and sexual reproduction

Answer 1

Asexual reproduction → generates offspring that are genetically identical to a single parent
Sexual reproduction → two parents contribute genetic information to produce unique offspring, creating variation.

Question 2

penis

Answer 2

delivers sperm through the urethra into the female reproductive tract

Question 3

bladder

Answer 3

muscular sac that stores urine until it is released through urethra

Question 4

prostate gland

Answer 4

surrounds a portion of the urethra and produces some of the fluid in semen to nourish sperm

Question 5

testes

Answer 5

produce sperm and the male sex hormone testosterone

Question 6

scrotum

Answer 6

contains the testes and epididymis and controls the temperature of the testes

Question 7

seminal vesicle

Answer 7

secretes a sugar-rich, thick fluid that nourishes the sperm

Question 8

urethra

Answer 8

tube that carries semen and urine out of penis

Question 9

vas deferens

Answer 9

thin muscular tube transports the sperm from the epididymis to the urethra

Question 10

epididymis

Answer 10

a narrow tube where sperm is stored

Question 11

vagina

Answer 11

tube that connects uterus to outside of body

Question 12

ovary

Answer 12

make eggs (ovum/ova) and hormones like oestrogen and progesterone

Question 13

fallopian tube

Answer 13

A tub that carries eggs from the ovaries to the uterus. Fertilisation happens here

Question 14

cervix

Answer 14

narrow ring of muscle that opens into the vagina from the uterus

Question 15

uterus

Answer 15

a hollow, pear-shaped organ with a muscular wall where foetus develops

Question 16

uterine wall

Answer 16

thickens during the menstrual cycle in preparation for implantation of fertilised egg

Question 17

pros & cons of asexual and sexual reproduction

Answer 17

asexual
Pros: no mating required, quick
Cons: low genetic variation, population is threatened when under stress

sexual
Pros: genetic variation, helps population survive when under stress
Cons: takes a long time, requires two individuals to mate

Question 18

define gene

Answer 18

DNA transferred from a parent to offspring, determining characteristics, provides instructions for building a specific protein

Question 18

mitosis

Answer 18

Prophase: Chromatin forms chromosomes (made of DNA & protein), nucleus disappears, spindle apparatus forms.
Metaphase: chromosomes line up down the middle of the cell
Anaphase: sister chromosomes are separated and moved to opposite ends of the cell
Telophase: reverse of prophase. Each new cell will start a new life in interphase. Chromosomes form into chromatin, nucleus returns, spindle breaks down.

Question 18

compare mitosis & meiosis (similarities & differences)

Answer 18

both use PMAT, cell division and and begin with a diploid cell

mitosis:
makes somatic cells (body)
growth, repair, replacement
2 identical daughter cells
46 chromosomes
diploid

meiosis
sex (gamete) cells
sexual reproduction & genetic diversity
4 daughter cells
23 chromosomes
haploid
crossing over

Question 18

meiosis

Answer 18

Prophase I: chromosomes line up with their homologous pairs and cross over, transferring genetic information and making recombinant chromosomes.

Metaphase I: Chromosomes in middle of the cell in pairs (different from mitosis)

Anaphase I: chromosome pairs pulled apart by spindle fibres

Telophase I: 2 newly formed nuclei, 2 new cells

Meiosis II, prophase II: spindles form

Metaphase II: chromosomes line up in single file, not pairs

Anaphase II: chromatids are pulled away by spindle fibres

Telophase II: nuclei reforms, 2 cells turn into 4 cells

Question 19

define allele

Answer 19

different versions of a gene found in the same chromosome

Question 20

define dominant & recessive

Answer 20

Dominant → allele overruled the other allele (recessive), always expressed if you have a copy
Recessive → a gene masked by a dominant gene, only expressed if you are

Question 21

define genotype & phenotype

Answer 21

Genotype → combination of alleles you have
Phenotype → expression of genotype (e.g. brown hair)

Question 22

define homozygous and heterozygous

Answer 22

Homozygous → two copies of the gene are the same Heterozygous → two copies of the gene are different

Question 23

define co dominance

Answer 23

both alleles of a gene are equally expressed in the phenotype, without one overshadowing the other.

Question 24

define sex linkage

Answer 24

Sex linkage is when a gene is found on a sex chromosome (X or Y), so its traits are passed on differently in males and females.

Question 25

outline the process of DNA replication

Answer 25

DNA replication is the process where the DNA molecule unwinds, and each strand serves as a template for creating a new complementary strand, resulting in two identical DNA molecules.

Question 26

define mutation

Answer 26

change in the base sequence of DNA

Question 27

distinguish between DNA and RNA

Answer 27

DNA: stores and transmits genetic information in the form of a double-stranded helix RNA: single-stranded molecule that helps carry out the instructions encoded in DNA

Question 28

define evolution

Answer 28

any change in the genetic traits in a population over many generations via variation, reproduction & natural selection

Question 29

define natural selection

Answer 29

1. Variation 2. Competition 3. Survival of the fittest 4. Reproduction 5. Population change

Question 30

Define fossil

Answer 30

reserved remains of ancient organisms.

Question 31

common ancestor

Answer 31

an ancestral group of organisms that is shared by multiple lineages (an ancestor they have in common)